I Know! I'll Fill It with a Sister-in-law - S1.E6

Kobeni's mother, Akane, who had always known the Mitsumines weren't human, tells Kobeni that she is no less thankful to them for saving her life. The next morning, Kobeni tries to learn more from Hakuya and Mashiro about their other forms, though Hakuya refuses to transform in front of her. As Kobeni turns her attention towards Valentine's Day, she ponders whether she should marry Hakuya or not. On Valentine's Day, Kobeni tries to work up the courage to give Hakuya some chocolate, but has trouble finding the chance. She finally gets the opportunity after her friend, Mayura Momouchi, comes over.