certifiably vs surely

certifiably

adv
  • Undoubtedly, demonstrably. 

  • With the potential for certification. 

  • To a great extent. 

  • Genuinely 

surely

adv
  • Certainly, undoubtedly. 

  • Without fail. 

  • With confidence. 

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