Would the meaning change if he says "don't" instead of "won't"? I won't ask a second time. VS I don't ask a second time.
Yes, the meaning would change here if you replaced "won't" with "don't". "Won't" is the contracted form of "will not" and "don't" is a contraction for "do not". So in this case, you would be saying "I will not ask a second time" instead of "I do not ask a second time". The second sentence is simple future tense and implies that he is not going to be asking a second time. The first sentence is present tense. When you combine the present tense of "don't" with the pronoun "I" and a present-tense verb, it often sounds strange when speaking to someone face-to-face in a conversation. So these types of sentences are normally only used in written English such as in the narration of literature where you are writing from your own perspective, called first-person point of view. Here's an example of first-person point of view when narrating literature: Ex: I tried to call him once but I don't call him again. In spoken English this sentence would be: Ex: I tried to call him once but I won't call him again.