When 'willing' is added, does this intensify or weaken the meaning of “I bet”?

Question

Although I could not see it in the fog, I knew that Gibbet Wood lay not far ahead at the top of Gibbet Hill. It would be wet and soggy in among the trees, but I was willing to bet that the police had not been there before me. (from The Weed that Strings the Hangman’s Bag)

Oxford says ‘I bet’ is ‘used to express certainty.’ If the word ‘willing’ (Oxford says; ready, eager, or prepared to do something) is added like the example, does it intensify or weaken the meaning of “I bet”?

Answer 1

I'd be willing to bet that it doesn't, at least for most readers.

In this example, the author isn't using willing to weaken or intensify the strength of the hunch. Instead, it seems the narrator has a plan that won't work if the police have been to a certain location first. He was going ahead with his plan, because he was willing to bet that the police hadn't been there yet. If he was, on the other hand, unwilling to take that chance, then he would have to execute another plan instead.

The author could have said, "I was betting the police had not been there before me," with very little change in the nuance of meaning.

Answer 2

Neither in this case. The author is indicating he was so sure of himself that he would have bet, but that he had no opportunity to do so.

Therefore the presumed level of certainty is the same as "I bet".

Answer 3

A bit, but while they're related I think they're best considered separately. While both are figurative and express that the speaker would be prepared to bet money (or something else) on the possibility addressed, they do so in slightly different ways.

"I'll bet it works", is claiming (though only figuratively) that they'll actually make that bet. Contracted to "I bet it works", it sounds almost looking for takers and offering odds (not a change in meaning, only in nuance).

"I'm willing to bet that it works" is a similar claim of confidence, made in a less informal manner (though still not very formal speech).

To me that reads not so much of less confidence, but as less emphatic. And the difference is more between the sort of thing that makes more sense as an exclamation or in direct addressing a particular person, over the sort that works both there and in a description or narration. However:

"I'm willing to bet all I own that it works", would be stronger than any so far, as would figuratively offering absurd odds: "I'll give you a million to one that it works", "I'll give you a guinea on a farthing that it works".