The Promise Episode 1

Raku Ichijo is a normal high school student. But, he also happens to be the son and heir to a yakuza clan called the "Shuei-gumi." Raku was never popular with the girls but 10 years ago, he met a girl and they promised each other that "they will get married" when they reunited. Raku still keeps the pendant that the girl gave him 10 years ago. One morning, while Raku was walking to school, a girl suddenly came falling from atop a wall and kicked Raku. That girl turned out to be, Chitoge Kirisaki, the girl that transferred to Raku's class.