Is the repentance of one who spoke ill of a girl and wronged her accepted, while he is remorseful for what he did, and cannot inform her for fear that this would lead to his divorce, and he has sought Allah's forgiveness for her and for himself? And how should his repentance be?

The door of repentance is open until the sun rises from the west. Therefore, you must repent with all its conditions fulfilled. If it is possible to absolve oneself from the woman generally without informing her, then that is good. If that is not possible, then one should frequently seek forgiveness for her and mention her with good.