assail vs encourage

assail

verb
  • To attack with harsh words or violent force (also figuratively). 

encourage

verb
  • To mentally support; to motivate, give courage, hope or spirit. 

  • To spur on, strongly recommend. 

  • To foster, give help or patronage 

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