I could never put my hands on a woman no matter what she says. I'm one of the most passive guys you'll ever meet, so it would take an awful lot to push me to that level. However, like someone on the first page said, there a lot of girls who have never been taught any discipline and will just haul off and hit you. Then what? It's a lose-lose situation because if you hit her back, you look like an *******. If you don't, you look like a punk. My advice is to react the way you want to react. Ultimately, despite what anyone else might say or think, you're the one who is going to have to deal with the fact that someone has just hit you. So if you're cool with just letting it slide, good. If you're not, well, defend yourself.