The Devil Does Exist(1998)

Akuma de Sourou

Shy Kayano finally works up enough courage to confess her feelings to the handsome Kamijo in a love letter. When the letter is intercepted by the notorious Edogawa Takeru--the devilishly handsome son of the school's principal--she is appalled, but even worse is her mother's engagement—to principal Edogawa! Now Kayano will have to live with this devil Takeru 24/7! How will she cope with this "living hell"?
(Source: CMX)

Included one-shots:
Volume 5: July
Volume 11: Flying Rabbit