Let’s put this in the correct perspective. For starters, she is under absolutely no obligation to marry him. If she chooses not to marry him, his punishment instead is to give her a full year of support, in addition to any other damages that Bais Din asseses. We are discussing only the case that she wants to marry him.
Let’s envision the following scenario: a man, in a moment of weakness, abuses her. It’s an erratic occurance, and he feels true remorse. She, however, now is likely to have a difficult time finding an appropriate shidduch. The Torah obligates him to make up for the difficulty that he caused her by forcing him to extend to her an offer of marriage. Again, if she has any reason to refuse, it’s her choice.