The two options which sound promising are "self-concept" - she has a concept of self and "egocentrism" - the excessive focus on the self and the inability to take others into account.
I think that the best answer is "egocentrism". She thinks of herself only in positive terms and does not question whether other people would be interested in her paintings - so she does not take others into account.
The guilty person will most likely deny the accusation. It is highly unlikely that he/she will immediately confess. Often times, the guilty person does not confess at all.
