I hear both (and their negatives: "I'm not sure" and "I'm not for sure"). I want to classify the "for sure" variety as regional Southern, since that's the context I most often hear it.

For example, take the "gimp" scene from Pulp Fiction. (Not that usages in the movies prove anything, mind you, but this is an example most people will recognize.) The character Zed is asked which of the captives he wants to "do" first, and he replies, with a distinct Southern accent, "I ain't for sure yet."

Can anyone point to evidence that this usage is regional, or class-based, or particular to any group of speakers?


Since @MrHen asked for more examples, I googled "I'm not for sure" and picked these off the first page:

"I'm really not for sure ~ what to do with you."

"I'm not for sure if I'm allowed to bump this ..."

"I'm not for sure which religion I am?"

"I'm not for sure when ..."

I think it's heard more in the negative than the positive. But I do hear it a lot. In the positive form, it's usually used in the form of a question? "Are you for sure?" instead of "Are you sure?"


I was listening to NPR last night and someone from Alabama who was being interviewed used "for sure" in the positive, as in "I was for sure that I wanted to do that."

  • for sure = certainly is common in AE, but not BE. Never heard "not for sure"
    – mgb
    Jun 3, 2011 at 15:07
  • Having lived in both Minnesota and Texas, I am actually a little confused by this question. "I'm sure" doesn't mean the same thing as "I'm for sure" in any sense that I can work out. Can you provide a few more examples?
    – MrHen
    Jun 4, 2011 at 14:00
  • @MrHen: See my edit.
    – Robusto
    Jun 4, 2011 at 14:11
  • I read those as "I am certain" and "I am, certainly".
    – misterben
    Jun 4, 2011 at 14:13
  • 1
    @misterben: I disagree. The usage is not a sentence adverb but a substitution of the one for the other: "for sure" is meant in the same way one would use "sure". How would "I'm not, certainly, which religion I am?" make any sense at all?
    – Robusto
    Jun 4, 2011 at 14:15

6 Answers 6


Cincinnati here, just a mile or so from Kentucky. I'm 57 years old, and only in the past year or so have I heard the phrase "I'm not for sure." It is used where one would say "I'm not sure." The two are interchangeable. Mainly I've heard it used by African Americans in their 30's and 40's, but also lately from one European American guy who's 29 years old. I've questioned a few of my co-workers, all in their fifties, and they say they've heard it for years, mainly from socio-economically challenged African Americans. Maybe Mr. Tarentino got it right. Or maybe he invented it.

  • Nah, he didn't invent it. I've heard it before and since that film, and just recently heard it used in the positive, by real-live people.
    – Robusto
    Nov 2, 2012 at 19:48

Note: Admittedly, I am challenging your assumption that these phrases mean the same thing. I do try to give an actual answer near the end... so your mileage may vary.

Well, I don't know how much help I can be since I still see these two things as meaning separate things:

I am not sure if I'm allowed to do this

I am not for sure if I'm allowed to do this

The usage and essential point are definitely the same, but I pull this difference between the two:

I don't know if I am allowed to do this

I am not confident I am allowed to do this

Since you can stick one in for the other and usually end up with a corresponding sentence that means virtually the same thing, I can understand the confusion.

Flipping things into the positive case makes it a bit easier to reveal:

I am sure

I am for sure

The first is a statement of quality of knowledge. The second is a statement of trustworthiness.

But, really, this is ungrammatical to me:

I’m really not for sure what I’d do without you.

This is pulled from your first linked example. The author is also waxing poetic; I wouldn't put too much faith in this usage. The other examples all work with how I see the difference between the sayings:

I don't know which religion I am / I am not confident which religion I am

I don't know when... / I am not confident when...

I don't know why I see this difference or if it holds any water. I suspect the source is the simple answer:

I am not sure / I am not for sure

The usage of "for sure" in other phrases again implies a subtle difference:

This is a sure thing

This is for sure

I wouldn't say "this is sure." If I heard someone say "this is a for sure thing" I would balk at it but parse it to mean "this thing is for sure."

So, to actually attempt answering your question, both phrases are used in Minnesota and Texas. I grew up in Minnesota and "sure" is used all over the place with the most common stereotype being, "Yeah, sure." If I asked someone, "Are you for sure?" they would understand the question to be "Can I be confident in you?" If I asked them "Are you sure?" they would understand the question to be, "Do you have any idea what you are talking about?"

Texas also uses "sure" but not nearly as often and I have not noticed (or admittedly thought about) them using "sure" and "for sure" as the same thing. In the event that they were I was probably attaching the meanings coming in from Minnesota.


"I'm sure." or "I am sure." would be used by the majority of educated English speakers.

You will most often here "I'm not for sure." from people who had not graduated past a K-5 education.

The use of "for sure." on it's own as a quick affirmative to another speaker's declaritive statement. example: Bob, "That sure was awesome play." (Baseball pitcher making a double play.) Joe, "For sure!"

People that use double negatives would also be be people that would use the "I'm not for sure." construction.

You don't state the context for which you want to use "I'm not for sure." But if you are writing and want you character to sound uneducated this would one of many different phrases you could use.

Regionally speaking, any American geographic area that has a lower than average high school (grade school even) graduation rate could suffer from this problem.

  • 1
    I agree, innit? It's effectively an indicator of poor linguistic competence rather than regional or class/economic "dialects". Sep 27, 2012 at 21:29

Found this in an International Dictionary, predominantly British:

—Idioms 13. for sure, as a certainty; surely: It's going to be a good day, for sure.

Taken from an American Dictionary:

In casual speech, when you agree with somebody’s statement, you may say “for sure.” Your date says ”That was outstanding tiramisu.” and you, wanting to show how in tune you are, reply “For sure!” You can also use the phrase to mean “for certain,” as in “I couldn’t tell for sure that the bench was wet until I sat on it.”But people often substitute this phrase when they should use plain old “sure,” as in “I couldn’t be for sure.” That should be “I couldn’t be sure.”

I would assume, as this is an American Dictionary, that it is used throughout America.

Couldn't find "not for sure", came up with this:

for sure not     

for sure, but not

origin: Scotland, mid-21st century, St. Andrews for sure, or for sure not?

  • 1
    Thanks for the effort you put into this, but I do know the meanings and how they're used. My question is about who uses "I'm [not] for sure" instead of "I'm [not] sure": whether it's a regional usage or not, etc.
    – Robusto
    Jun 4, 2011 at 3:33
  • Oops! Mucked up big time!
    – Thursagen
    Jun 4, 2011 at 3:43
  • 1
    And yet people see fit to upvote an admittedly non-responsive answer. Sometimes I despair ...
    – Robusto
    Jun 4, 2011 at 17:17

I know this is a big jump in time since this thread was active, but dealing with a customer care case worker for a large manufacturer over the last few weeks, although she seems fairly well educated and doesn't seem to have a particularly regional accent or dialect that I can detect, she has numerous times used the phrase "I'm not for sure" in place of "I'm not sure", but the rest of her speech seems normal, not colloquial, without double negatives, etc. I don't know where she grew up, but I think she did mention in relation to a hobby that she is from a rural area.


"For sure" is an interjection, "sure" is an adjective. No native speaker of American English would say "I'm for sure" except as a joke.

Jill: Oh, so you wrote, "ho fo sho"?

Andy: Yeah, I remember that girl, she was a ho... for sho.

  • 1
    This is not true. You are not responding to the sense in which I am formulating the question.
    – Robusto
    Jun 4, 2011 at 15:52
  • 1
    @Robusto -- that's California-raised Quentin Tarantino's idea of how rural Southerners speak. I've never heard anyone actually say that aloud -- but the same is true of most of Tarantino's dialog. Jun 4, 2011 at 15:59
  • 2
    -1; Native speakers do say "I'm for sure." Not typically in such a condensed form, but I do hear it from time to time.
    – MrHen
    Jun 4, 2011 at 16:00

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