doubt vs fidelity

doubt

noun
  • Disbelief or uncertainty (about something); (countable) a particular instance of such disbelief or uncertainty. 

verb
  • To be undecided about; to lack confidence in; to disbelieve, to question. 

fidelity

noun
  • Accuracy, or exact correspondence to some given quality or fact. 

  • Faithfulness to one's duties. 

  • Loyalty to one's spouse or partner, including abstention from cheating or extramarital affairs. 

  • The degree to which a system accurately reproduces an input. 

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