Helena

Helena is a princess but she secretly became a knight by changing her identity. She is a very skilled in swordman ship. So it wasn't that difficult to be a knight. And no one even recognize her that she is the princess. She is very confident with the decision she made. The queen and king wanted her to marry a noble man and live like a lady but she refused it, because she doesn't want to dependent on any man. She always wanted to be a warrior and a knight. So she escaped from the castle and went to another kingdom with the help of her some noble friends. And became a knight. You were the prince of the kingdom where she is now.