Lucky, Aren't you, Sei-chan

Okumura Hijiri, a girl who can see spirits and ghosts, finds out she's engaged to a kitsune, Gin, due to a forgotten promise of ten years ago. Gin tries to convince Hijiri to marry him, but things are made more complicated by Toono Kazuhiko, the boy Hijiri loves, and Rin, Gin's ex-girlfriend.