If you’ve already agreed to the truth, it has nothing left to take from you.
Most people protect themselves from accurate descriptions. They flinch, explain, change the subject. A person who has stopped doing that is in a different position. The true thing may be unpleasant to hear, but it can’t threaten them, because they consented to it in advance.
That is a moral commitment before it is anything else. It means holding yourself to a reference you didn’t choose for comfort, and checking yourself against it when nobody is asking you to.
It has a consequence people don’t expect: you become very hard to wound with words. A true remark is one you’d accept from anyone, and a false one has nothing to land on.
So when something still hurts, it’s worth asking what it was.