not want to know about something

Từ điển Oxford Advanced Learner 8th

not want to ˈknow (about sth) idiom
(informal)to take no interest in sth because you do not care about it or it is too much trouble
•I've tried to ask her advice, but she doesn't want to know (= about my problems).
•‘How much was it?’ ‘ You don't want to know ’ (= it is better if you don't know).
Main entry: ↑want_idiom