I think he is not tricking him. I guess they already forming their feeling, after getting raped by the villager, the ghost snake find out the truth. maybe in the process our Mc die miserably and that's the biggest ghost snake regret. that's why his regret for not able to protect this kid is bound to a place where he buried the MC in the past after getting raped and waiting for the reincarnation. sadly since MC is absorb negative energy from his past life he became womenizer (?) and that's how the ghost snake starting jealous and want MC to remember about his past life.
totally my theory, HAHA
This definitely works
So can we all agree that the ML is the snake from the beginning? And he tricked the MC ?