I feel like this story doesnt know what it wanted to be. There was almost no reason for the fantasy elements. Half of it seemed grounded in reality the whole business, stealing of jewellery etc. That was a good plot idea. The other half was fantasy that never really got explained. Just do one idea and stick with it.
I feel like i could have come up with a better reason why Lin kept fainting all the time. His past life or part of his spirit or soul or whatever they were trying to get at could have been the villain in the love story between the MC and his sister. He could have killed her by accident causing the MC to punish him and then he was reborn. In his new life, he could have fallen in love with the MC while his past life tries to warn him that he did this before and he didnt get the Happy Ending. In this life, the MC could have realized that he made a mistake and tried to make it up to him. There a fantasy love story. I still cant understand what the point of the fantasy elements in this story was.
I did enjoy the side couples.