self confidence

I think I understand the idea of self confidence. You trust yourself, you learn by failure , you are willing to feel any emotion, you manage your thoughts about yourself.
My partner seems to have this in abundance. He has not worked in 4 years and says he has been looking. He is applying for jobs that he believes he can do. He has enough self confidence to keep up this – to keep on trying for years to come, but it is financially very difficult for my family to sustain. My question is, when is self confidence not enough? When does he just get a job versus the job he knows thinks he deserves?