cold feet vs confidence

cold feet

noun
  • Used other than figuratively or idiomatically: see cold, feet. 

  • A feeling of nervousness or anxiousness causing one to reconsider a decision about an upcoming event. 

confidence

noun
  • 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-assurance. 

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