Sore Yuke Nanpa-kun

A young man named Hidetsugu dreams of having a girlfriend. One day he meets a girl on the street and tries to impress her. However, a rival appears unexpectedly and the girl is unable to choose between them. The two have a conversation and agree that the stronger men is the one who has more experience with women. Hidetsugu then embarks on a quest to meet young women and work his charms on them.

[From Mobygames]