Ojousama wa Oyomesama

Towako, the daughter of a high-class family, is approaching her eighteenth birthday—and the marriage she was promised as a child. She is expected to marry Yuuga, a young man born on the same day, at the same time, and in the same year as she was. But their first meeting does not go as Towako might have hoped: Yuuga is incredibly mean to her. Now she must face the prospect of marrying a shy, cool young man who has made a decidedly poor first impression.