Kanojo ga Kawaisugite Ubaenai

As one of the seven demon princes of Hell, Shion strives to become the next demon king by passing the Demon King Succession Exam. However, unlike in previous years that required the princes to steal a human soul, Shion's new objective is to steal his designated human's heart—to be more exact, her virginity. In order to get closer to his target, the fragile and all-too-innocent Umeko Makimura, Shion disguises himself as a human and infiltrates her school as the new transfer student. Relying on the methods he has read in shoujo manga, Shion creates the most romantic situations he can come up with to deepen their relationship. However, the more Shion tries to steal Umeko's heart, the more he realizes that it's his own heart which may have been stolen instead.