Is a man sinful for continuing to communicate with a woman who became infatuated with him, trying to guide her religiously, and then informing her husband of this, knowing that he regrets his action and has repented to Allah?

The man erred by exceeding the bounds in speaking with the woman, especially after learning of her inclination towards him. A prohibited act is not rectified by a good intention, and a praiseworthy goal does not justify a blameworthy means. The Prophet, peace and blessings be upon him, forbade speaking with women except with the permission of their husbands. His duty was to inform her husband and admonish him. However, since he has repented and shown remorse, his repentance is welcomed for acceptance, and he must fulfill his pledge to refrain from speaking with foreign women.