faltering vs sure thing

faltering

adj
  • hesitant, halting 

noun
  • hesitancy 

sure thing

noun
  • That which is certain. 

intj
  • An affirmative reply; yes; certainly. 

  • A polite reply to thank you. 

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