What do you say to a person who fears God, but fell into Satan's trap and fondled his niece and caressed her, but did not commit adultery with her, and regretted that?

Preludes to adultery, such as looking, touching, and kissing, are forbidden and are a means to it. Committing such acts with maharim (unmarriageable kin) is even more strictly forbidden.

Whoever has committed any of these acts with his niece must repent with sincere repentance, increase in good deeds, and avoid being alone with her and looking at her if he senses an inclination towards suspicion. He must remember that a girl's paternal uncle is like her father and should be a protector of her honor, not an aggressor against it, and that recompense is according to the type of deed.