put at ease vs unnerve

put at ease

verb
  • To evoke or cause someone to be relaxed or calm. 

unnerve

verb
  • To make somebody nervous, upset, alarm, shake the resolve of. 

  • To deprive of nerve, force, or strength; to weaken; to enfeeble. 

How often have the words put at ease and unnerve occurred in a corpus of books? (source: Google Ngram Viewer )