confidence vs surety

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. 

surety

noun
  • That which makes sure; that which confirms; ground of confidence or security. 

  • A promise to pay a sum of money in the event that another person fails to fulfill an obligation. 

  • One who undertakes to pay money or perform other acts in the event that his principal fails therein. 

  • A substitute; a hostage. 

  • Evidence; confirmation; warrant. 

  • Certainty. 

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