Rape proof means you are willing and able to stop anybody from raping you.
Ya, I thought that would be self-explanatory.
I thought it might be some technical certification, like ISO-RAPEPROOF. "Hello potential employer! Here is my Rape Proof Certificate, you can see I re-upped last spring."
So it's just a matter of declaring, "no-one will rape me"? I know rape is a crime of violence, hatred, and power, not one of sexual passion. So rapists are commonly, like most bullies, looking for a victim. Essentially "rape proof" just means that you're declaring you think you're enough of a badass that most potential rapists would not consider you a victim, and those that would, you feel capable of fending against?