I was always looking outside myself for strength and confidence, but it comes from within. It is there all the time. -Anna Freud.
There are admirable potentialities in every human being. Believe in you strength and your youth. Learn to repeat endlessly to yourself. It all depends on me. -Andre Gode.
Having once decided to achieve a certain task, achieve it at all costs of tedium and distaste.The gain in self-confidence of having accomplished a tiresome labor is immense. -Norman Vincent Peale.
Believe in yourself ! Have faith in you abilities ! Without a humble but reasonable confidence in your own powers you cannot be successful or happy.