トゥルーハート

"True Heart" is set in a medieval fantasy country Riku, and the player controls the young prince Gerard, the only heir to the throne. According to the country's tradition, every prince has to undergo a series of trials when he turns seventeen, to make sure that he would be a responsible ruler. However, our young hero is much more interested in other kind of "trials", those involving himself and members of the opposite sex. Surrounded by young and pretty girls of different social backgrounds and personality types, the prince has to find out which one holds the key to his heart... and not just his other body parts.

[From Moby Games]