assurance vs promise

assurance

noun
  • The act of assuring; a declaration tending to inspire full confidence; something designed to give confidence. 

  • Subjective certainty of one's salvation. 

  • Firmness of mind; undoubting steadiness; intrepidity; courage; confidence; self-reliance. 

  • Insurance; a contract for the payment of a sum on occasion of a certain event, as loss or death. Assurance is used in relation to life contingencies, and insurance in relation to other contingencies. It is called temporary assurance, in the time within which the contingent event must happen is limited. 

  • The state of being assured; total confidence or trust; a lack of doubt; certainty. 

  • Excessive boldness; impudence; audacity 

  • Any written or other legal evidence of the conveyance of property; a conveyance; a deed. 

promise

noun
  • an oath or affirmation; a vow 

  • A transaction between two persons whereby the first person undertakes in the future to render some service or gift to the second person or devotes something valuable now and here to his use. 

  • A placeholder object representing the eventual result of an asynchronous operation. 

  • Reason to expect improvement or success; potential. 

verb
  • To commit to (some action or outcome), or to assure (a person) of such commitment; to make an oath or vow. 

  • To give grounds for expectation, especially of something good. 

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