Kyou kara Prince

The main character lives in a poor area. He is called the black prince because he resembles the prince of the Supple Kingdom. One day, he is abducted by someone from the Nordia Kingdom. They disguise him as the prince of the Supple Kingdom and send him to the castle of the Supple Kingdom while the king, the queen, and the prince are away. However, the prince comes back to the castle earlier than they expected while the protagonist is also there. After a serious crisis, he successfully manages to exile the real prince.... He enjoys his life there, but he hears the king and the queen are coming back in three weeks. He decides to conciliate three princesses to his side to get through his difficult situation. Like this, he pretends he is the real prince and approaches them....