promising vs undoubting

promising

adj
  • Encouraging and inspiring confidence. 

  • Showing promise, and likely to develop in a desirable fashion. 

  • a promising young apprentice 

noun
  • The act of making a promise. 

undoubting

adj
  • Experiencing or harboring no doubts; entirely confident. 

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