certifiably vs truthfully

certifiably

adv
  • Genuinely 

  • With the potential for certification. 

  • To a great extent. 

  • Undoubtedly, demonstrably. 

truthfully

adv
  • Frankly. 

  • In a truthful manner 

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