averment vs indubitability

averment

noun
  • The act of averring, or that which is averred; positive assertion. 

  • verification; establishment by evidence. 

  • A positive statement of facts; an allegation; an offer to justify or prove what is alleged. 

indubitability

noun
  • The quality or state of being indubitable. 

  • Something that cannot be doubted; a certainty. 

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