in one's heart (of hearts) vs internally

in one's heart (of hearts)

internally

adv
  • Inwardly; spiritually. 

  • With regard to internal affairs. 

  • In an internal manner; within or inside of external limits; in an inner part or situation. 

How often have the words in one's heart (of hearts) and internally occurred in a corpus of books? (source: Google Ngram Viewer )