What is the right of the apartment owner over a man who committed adultery with a woman in his apartment and has repented of his action? And is it obligatory for him to ask for the owner's forgiveness and pardon for this deed, given that it is impossible to inform him of what happened?

The man must repent to Allah for the sin he committed. Repentance entails abandoning the sin, regretting it, and resolving not to return to it.

The noble verse: (And establish prayer at the two ends of the day and during parts of the night. Indeed, good deeds do away with evil deeds. That is a reminder for those who remember) is evidence that good deeds erase evil deeds, and this applies to all Muslims.

Both the young man and the young woman must repent to Allah and seek forgiveness for what they committed against the apartment owner, because what they did is considered a betrayal of trust. They are not required to inform him of it.

It is not permissible for the man to inform the landlord of what happened, as this would be publicizing a sin. The Prophet, peace and blessings be upon him, commanded concealment of sins and not publicizing them.