soften up vs tenderize

soften up

verb
  • To make softer. 

  • To become less committed to something. 

  • To appease someone in order to make them more receptive to an idea or proposal. 

tenderize

verb
  • To make (something, especially meat) tender. 

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