confirm vs prove out

confirm

verb
  • To assure the accuracy of previous statements. 

  • To administer the sacrament of confirmation on (someone). 

  • To strengthen; to make firm or resolute. 

prove out

verb
  • To turn out to be feasible, accurate, true, satisfactory, as expected, hoped, stated, etc. 

  • To demonstrate the feasibility of; to show or be shown to be feasible, accurate, true, satisfactory, as expected, hoped, stated, etc. 

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