A--- The term "Sincere Repentance" implies the existence of three things:

Giving up the sinful deed committed, regretting it, and showing firm will not to return to it for ever. If there is an oppression against anyone else, one should beg him for forgiveness before the coming of the Day of Resurrection when everyone will inevitably be retaliated. Moreover, this is the sort of oppression Allah the Almighty will not let an atom of it go without reckoning. Narrated Abu Hurairah (May Allah be pleased with him): Allah's Messenger (Peace be upon him) says: "Whoever has oppressed another person concerning his reputation or anything else, he should beg him to forgive him before the Day of Resurrection when there will be no money (to compensate for wrong deeds), but if he has good deeds, those good deeds ,will be taken from him according to his oppression which he has done, and if he has no good deeds, the sins of the oppressed person will be loaded on him. " (Sahih Bukhari)