Sometime in the future society has realized that those who are hurt tend to spread hurt. Depressed people tend to bring those around them down emotionally, and those who have been victims of crime and have lost any hope of being happy tend to be less productive citizens.
With this in mind criminals who have committed any crime that results in victims and family of those victims to feel that live will never again present them with moments of joy are sentenced to a period of time in which they are nothing more than the property of those victims. So these victims do not hold any hatred towards those that are assigned to them they are given the convicted criminals that have had nothing to do with the crime they were affected by. So the criminals are not tempted to do harm to their new masters/mistresses they are given an implant that will immobilize them if they do anything which warrants their new owners to activate it. When the owner is sleeping and therefore vulnerable to any harm their slave may commit they are able to immobilize that slave until they awake. Lastly the nature of the crime committed by the prisoner the master is assigned is never given so it will not repulse or interfere with that persons ability to satisfy there deepest desire.
I would be open for suggestions and could play the role of either.