enthusiastic vs single-hearted

enthusiastic

adj
  • Relating to enthusiasm, or divine possession. 

  • With zealous fervor; excited, motivated. 

single-hearted

adj
  • Devoted; unambivalent and dedicated. 

  • Having an honest heart; straightforward, free from duplicity. 

How often have the words enthusiastic and single-hearted occurred in a corpus of books? (source: Google Ngram Viewer )