What is the ruling on denying a personal matter that was told to someone and attempting to convince him to forget it, and what is the ruling on deceiving oneself in the same way to forget a painful incident?

If you lied to the man to convince him, then lying is forbidden and leads to wickedness and the Fire, and its perpetrator is written down as a liar with Allah. And the thought that what occurred did not occur, there is no sin in it. It is better for you to occupy yourself with what benefits, and to repent to Allah for what has passed, and ask Him to avert evil from you.