What is the ruling on sexual fantasies, such as love stories or imagining perversion, that come to a girl before sleep, knowing the prohibition of perversion, while she continues her bedtime remembrances?

These fantasies are not sinful for a person, because Allah has forgiven this Ummah for what they contemplate in their hearts, as long as they do not act upon it or speak of it. However, a Muslim should not indulge in them, as they might lead to falling into what is forbidden. It is better to contemplate the names and attributes of the Lord, His blessings and bounties, and His cosmic and Quranic signs. You must strive against intrusive thoughts (waswas) and not indulge in them, for indulging in them leads to great evil.