There are a lot of similarities between these two. First of all the main female lead is the same actress and the second male lead in both of these is the same. If you watch cruel romance, remember ying dong? Well his brother in cruel romance is playing his father in stay with me. I find that a bit weird, but his character still does everything he can for his family. Also the main lead in here also does so much for the female lead in secret, like in cruel romance. The main female lead does some crappy things to the main lead as well. Also there is the situation of "killing" her father.