I am satisfied with the ending. If you notice the way Ji Chu open his jacket in the last scene you know it is him. He went to find her in her world just like he promised.
I am not one to always want or need a happy ending. Sometimes it just doesn't make sense to end on a happy note. But for the first time I really do need a happy ending for these two. They are so darn cute together. I can't imagine one without the other.