Hey. I have read this manga before but I can't remember the title. The story goes like thi...

Hey. I have read this manga before but I can't remember the title. The story goes like this. It is about a guy where needs to get a contract signed by the prince (I think it is something about a diamond or something). There were also some political issues and all. At the end the prince meets him back after 1 or 2 years in Japan and got back together with him. In between he was also kidnapped by the prince's brother. Additionally, the guy and the prince has met before when they were small. I hope this information is enough :P