ambiguity vs sure bet

ambiguity

noun
  • words or statements that are open to more than one interpretation, explanation or meaning, especially if that meaning cannot be determined from its context. 

  • The state of being ambiguous. 

sure bet

noun
  • Synonym of safe bet, good bet, fair bet 

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