Question:

Is it permissible for someone to frankly tell someone else about his defects?

Answer:

It is permissible if it is done gently and with the intention of giving advice so that such a person might be prevented from making a mistake. On the other hand, it is impermissible if it is done out of the intention to defame or reproach.

May Allah grant us success. May peace and blessings be upon our Prophet Muhammad, his family, and Companions.