Makasenasai!!

Hiromi is a high school girl who has never had a boyfriend but has always enjoyed matchmaking. Riko (her younger sister) is experiencing her first love. To make it a success, Hiromi tries to find out who is the special someone in her sister's heart. To her surprise, it is Nan--best known to be the school's most flirtatious guy. It would appear that Hiromi has to face her toughest matchmaking challenge ever. (Source: B-U)