to fool yourself
Está mal engañar a la gente, pero es aún peor engañarte a ti mismo.
It's wrong to deceive people, but it's even worse to deceive yourself.
¿Por ayudarte a engañarte a ti mismo?
Why would I help you fool yourself?
— Das weiße Band - Eine deutsche Kindergeschichte (2009)
Don't deceive yourself.
Stop fooling yourself.