What is the ruling on one who committed adultery with a woman and paid her money, then took it back from her without her knowledge, and asked her for forgiveness without returning the money?

Compensation for an unlawful benefit (such as fornication) is not owned by the recipient. Scholars have differed on whether this compensation should be returned to the one who paid it or not. The majority view is that it should be returned to the payer because it was seized by an unlawful seizure. However, the more authoritative narration from Imam Ahmad and Ibn Taymiyyah is that it should not be returned to the payer, but rather spent on the interests of Muslims or given as charity. Ibn al-Qayyim preferred the view that the payer is not entitled to reclaim the compensation because he paid it voluntarily and received his unlawful benefit. This prevents combining the compensation with the compensated benefit and is considered aiding in sin. It is not permissible for the recipient to enjoy this money due to the impurity of its earning, but not because it was taken unjustly from someone. The way to dispose of it and complete one's repentance is by giving it in charity. If the recipient is in need, they may take what suffices their need and donate the remainder. This ruling applies to all impure earnings due to the impurity of their compensation, and the ruling of its impurity does not necessitate its return to the payer.