A book recommendation that led to their reunion after so many years of separation?

The female lead was called Shui Ling, and the male lead's family was from the underworld. Later on, because of the misunderstanding, Shui Ling became cold-blooded again.
The female lead's sister and the male lead's brother were a couple. There was also a little campus inside.
[Additional question: Shui Ling has been helping a police officer undercover!]

Answer 1

She recommended "Secretly Tempted." The female lead was Shui Ling, and the male lead came from a wealthy family. In the plot, the female lead transferred to the male lead's class. At first, the male lead was very fierce to her, but later, due to a misunderstanding, he began to change his opinion of the female lead. I hope you like this fairy's recommendation. Muah ~😗