assertion vs vow

assertion

noun
  • Something which is asserted; a declaration; a statement asserted. 

  • A statement in a program asserting a condition expected to be true at a particular point, used in debugging. 

  • A statement or declaration which lacks support or evidence. 

  • The act of asserting; positive declaration or averment. 

  • Maintenance; vindication 

vow

noun
  • A declaration or assertion. 

  • A solemn promise to perform some act, or behave in a specified manner, especially a promise to live and act in accordance with the rules of a religious order. 

verb
  • To declare publicly that one has made a vow, usually to show one's determination or to announce an act of retaliation. 

  • To make a vow; to promise. 

  • To make a vow regarding (something). 

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