assertion vs avowal

assertion

noun
  • The act of asserting; positive declaration or averment. 

  • 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. 

  • Maintenance; vindication 

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

avowal

noun
  • An open declaration of affirmation or admission of knowledge. 

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