energize vs hearten

energize

verb
  • To invigorate; to make energetic. 

  • To supply with energy, especially electricity; to turn on power to (something). 

hearten

verb
  • To give heart to; to encourage, urge on, cheer, give confidence to. 

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