dampen vs hearten

dampen

verb
  • To lessen; to dull; to make less intense (said of emotions and non-physical things). 

  • To become damped or deadened. 

  • To become damp or moist. 

  • To make damp or moist; to make moderately wet. 

hearten

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

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