confidence vs self-belief

confidence

noun
  • Self-assurance. 

  • A feeling of certainty; firm trust or belief; faith. 

  • Information held in secret; a piece of information shared but to thence be kept in secret. 

self-belief

noun
  • Trust in one's positive characteristics; self-confidence; self-worth. 

How often have the words confidence and self-belief occurred in a corpus of books? (source: Google Ngram Viewer )