expectation vs promise

expectation

noun
  • The prospect of the future; grounds upon which something excellent is expected to occur; prospect of anything good to come, especially of property or rank. 

  • The act or state of expecting or looking forward to an event as about to happen. 

  • The value of any chance (as the prospect of prize or property) which depends upon some contingent event. 

  • The first moment; the long-run average value of a variable over many independent repetitions of an experiment. 

  • The arithmetic mean. 

  • The leaving of a disease principally to the efforts of nature to effect a cure. 

  • That which is expected or looked for. 

promise

noun
  • Reason to expect improvement or success; potential. 

  • 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. 

  • an oath or affirmation; a vow 

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 expectation and promise occurred in a corpus of books? (source: Google Ngram Viewer )