How often does a girl threaten to cut a man's ball off if he breaks if off with her?

Does she say it jokingly or is there actual intent to the threat? I would say that is not often that a girl will threaten physical harm on you just because you end up breaking up with her. If you are the one that initially proposed then she should know that you are become more invested in the relationship. She should trust you more if you do something like that. I guess she is overreacting or something about the situation. It also lets you know that she very much loves you and wants to be with you.