The Princess' Man (공주의 남자)

A tragic love story between the daughter of Prince Soo Yang and the son of Kim Jong Seo. The son of Kim Jong Seo, Seung Yoo (Park Shi Hoo), is a handsome and wise man who carries a noble quality. Princess Se Ryung (Moon Chae Won), a daughter of King Se Jo, aka Prince Soo Yang, is a cheerful, lively lady with a strong curiosity and bold personality. They fall in love instantly but later they find out that their parents are sworn, enemies. It's a Chosun dynasty version of “Romeo and Juliet”.

(Source: DramaWiki)