If you are into time travelling plots which makes your mind goggling, this may be the one you are looking for. Although the main who travels into the past is a guy, he tries to change the fate of his family and along the way there is romance blooming as well. For more information, WATCH THE DRAMA ;)
It is also a rom-com historical drama, but contains more actions. The main girl here also surrounds a birth secret that she does not know of until the romances between the three main characters develop (the other one is a second male lead played by Jang Geun Suk). In LITM, it is Byung Yeon who finds out Ra On's true identity, but in HGD, it is Lee Chang Hwi (played by Jang Geun Suk) who finds the true identity of the main girl. Hong Gil Dong may not be a crown prince, but he is a illegitimate son of a high rank minister. Also, the main girl played by Sung Yu Ri knows martial arts and can beat most of the men she fights. She is a cute strong-willed girl who is free-hearted to all the people she meets.