belief vs doubtfulness

belief

noun
  • Mental acceptance of a claim as true. 

  • Religious faith. 

  • One's religious or moral convictions. 

  • The quality or state of believing. 

  • Faith or trust in the reality of something; often based upon one's own reasoning, trust in a claim, desire of actuality, and/or evidence considered. 

  • Something believed. 

doubtfulness

noun
  • The state or quality of being doubtful; doubt; uncertainty. 

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