Will she be sinful for having intercourse with her husband on Thursday after seeing white discharge, and then drops of blood appearing on Friday and Saturday after performing ghusl for janabah, given her apprehension about informing her husband?

If the questioner sees the white discharge on Thursday, she has become pure, and whatever she sees after that is not menstruation, because the minimum period of purity is fifteen days. If the white discharge is not her usual sign, then if the spots occur during her customary days, they are menstruation, and if they occur outside of them, they are not menstruation. There is no sin upon the questioner for informing her husband of her purity due to her strong presumption, and there is no sin upon him for having intercourse with her.