alleviation vs reassurance

alleviation

noun
  • the act of alleviating; relief or mitigation. 

  • the act of reducing pain or anything else unpleasant; easement 

reassurance

noun
  • Reinsurance. 

  • The act of confirming someone's opinion or impression. 

  • The feeling of being reassured, of having confidence restored, of having apprehensions dispelled. 

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