In this world(like our own), I wouldn't put much stock in the justice system(especially given that slave collars exist). Systems tend to protect those in power, so this person might get off with a slap on the wrist. Further, predators such as this have high recidivism rates and will opt to be better prepared rather than quit such activities. I do think some form of medical intervention(ie counseling, meds, removing brain tumors, etc) might serve to rehabilitate such individuals, but I lack data to draw such a conclusion. In this setting, though, I doubt many of these things exist.
On another note, I disagree with the idea that attempted rape should be treated any less harshly that rape itself. The attempt itself may have already caused substantial harm to the victims as well as revealed the perpetrator's willingness to commit rape.