Ok, I learned that using "Will" when we're so sure that we will do something.
The boss: Don't be late tomorrow
The employee: I won't, sir!
If we say "I wouldn't", then it seems that we think that thing is impossible & this could make the boss upset.
So, it seems that we should use "Will" when we really want to do things for someone
But this said using "would" to make it more polite
In direct request or suggestions we use type 1 conditional. To make a request or suggestion more polite, we use type 2 conditional. Compare:
- It will be nice if you help me. (direct request - Type 1)
- It would be nice if you helped me. (less direct, more polite request - Type 2)
And other example,
If you write her a letter, I'll send her my best wishes.
If you wrote her a letter, I'd send her my best wishes.
If we say "will you help me?" then it seems that we just care about ourselves & we are forcing people to help us.
But, "would you help me" make the listener thinks that that is impossible. Thus, the question is more polite.
So, it seems that we should use "Would" when we really want someone to do things for us