Castration
That would be easy for them. Rapist who get away with their crime will soon rape another. Cut their penises and legs and arms and let them live if they can. Or the government can blind them but also provide them a rope if they want to hang themselves after it. I think this is a better punishment for such crime.
right castration wont lead them to chance but only giving them another chance to make rape.what is needed for them to be killed they must not let live.either kill them or they cut own life the victims will have that bad experience in mind for all of their life