betray vs promise

betray

verb
  • To prove faithless or treacherous to, as to a trust or one who trusts; to be false to; to deceive. 

  • To violate the confidence of, by disclosing a secret, or that which one is bound in honor not to make known. 

  • To deliver into the hands of an enemy by treachery or fraud, in violation of trust; to give up treacherously or faithlessly. 

  • To disclose or indicate, for example something which prudence would conceal; to reveal unintentionally. 

  • To mislead; to expose to inconvenience not foreseen; to lead into error or sin. 

  • To lead astray; to seduce (as under promise of marriage) and then abandon. 

promise

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. 

noun
  • 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. 

  • an oath or affirmation; a vow 

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