Bewitched
What do you think Toyo-o continues to be involved with Manago even after he suspects that she is a demon of some sort?
Toyo-o involvement with Manago first started the very day both of them met at the fisherman hut waiting on the rain to stop, secondly when Toyo-o had a dream the next morning when Manago offers wine and give him food to eat in his dream, and later during the day when they met physically at Manago house, she offers him food and wine as well.
The reason Toyo-o continues involvement with Manago even after he suspects that she is a demon of some sort was because Manago had cast a love spell on him both physically and spiritually, in my own words I believe that it was because of the food and wine that was given to him in his dream and physically.
Because Toyo-o was under a love spell by Manago, he never had control over her and whatever she told him about herself convincingly was easy to believe, and in addition, it was also easy to locate him everywhere he went.