When a man promises to do anything to save the relationship after the woman has broken up with him can that create even more resentment?

My question about this would be how sincere the man is about keeping his promise and is it a promise that he can keep at all. It is very easy for someone to make a promise, but a lot of times it is a lot more difficult to keep the promise, and many times the promise is nothing more than empty words to get another person to do what they want. I know this does not directly answer your question, but it would be my guess that it definitely could create more resentment, either for you if the promise is not kept, or for him if he feels it is not something he wants to keep after you are back together. If you are considering going back to him, I think you should have the word "anything" defined. That way, you will both know what to expect from the start.