Inherited Boyfriend. -From Now On, You're Mine-

"In accordance with Lady Murasaki Sakurada's will, her fortune and myself belong to you now." A man saves Ritsu from being hit by a car. He's beautiful, with hair as white as snow, but he's claiming that he belongs to her now! The man, Ren, blithely explains that he's come to the orphaned Ritsu in accordance with the will left behind by Ritsu's great-grandmother. Ritsu is shocked and confused, but the man seems nice enough... And his fingers and gaze seem to seek her almost madly...

(Source: MangaPlaza)