certain vs sure thing

certain

adj
  • Unfailing; infallible. 

  • Known but not specifically named; indeterminate; indefinite; one or some; sometimes used independently as a noun, and meaning certain persons; see also "one". 

  • Fixed or stated; regular; determinate. 

  • Not to be doubted or denied; established as a fact. 

  • Sure, positive, not doubting. 

  • Actually existing; sure to happen; inevitable. 

pron
  • Unnamed or undescribed members (of). 

det
  • Having been determined but not specified. 

sure thing

intj
  • An affirmative reply; yes; certainly. 

  • A polite reply to thank you. 

noun
  • That which is certain. 

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