Ummm, he's not though, I mean do your eyes work? Like his face doesn't go from a smile to a menacing grimace every time the dude leaves eyeshot? His entire plan is to manipulate him into trusting him so he can ruin the life of the dude and his family for revenge on behalf of the ghost of his mother that Norman Bates motherfucker's crazy ass hallucinates on an apparently consistent basis. I mean, did ya miss the tilte of the entire story? Where what I just said is happening but hasn't happened... YET?
My eyes work perfectly fine, but I doubt your brain does for being so fucking rude. Forgive me for interrupting your dramatic delusions, but wait till you’re asleep to dream up these sort of theories that you manufactured.
He clearly got close to him for revenge but he is having a change of heart, which we can all see. But if you have a different opinion or theory, you can always present it like a sensible person, not someone that has no home training.
Anyways, it’s not my duty to spoon-feed you common sense and since you clearly cannot have a decent conversation with someone without resorting to insults, this is definitely the last reply you’re gonna get from me until you learn some proper manners. I’m definitely the wrong one.

I kinda want the pink-haired girl to mind her business. Exposing the truth to Qingyu is gonna hurt him too much. It is either he finds out himself or Cheng tells himself by himself.