Hatsukoi no Shounen wa Reitetsu Kishi ni Hyouhen shite Imashita Zenryoku de Kokuhaku Sareru Nante Souteigai desu!!

Ravi, a girl born into a wealthy merchant family, begins to cherish Cyril, the son of an earl, who protects her from robbers. However, after Cyril's father passes away, she loses contact with him... When they meet again seven years later, Cyril has become a knight of the Royal Knights, but his gentle and calm personality has changed completely, and he coldly dismisses Ravi, saying he "doesn't remember" her. But there's no way that the overly opinionated Ravi will back down so easily!

(Source: Comic Walker, translated)