attest vs vow

attest

verb
  • To put under oath. 

  • To affirm to be correct, true, or genuine. 

  • To certify in an official capacity. 

  • To supply or be evidence of. 

  • To certify by signature or oath. 

vow

verb
  • To make a vow regarding (something). 

  • To declare publicly that one has made a vow, usually to show one's determination or to announce an act of retaliation. 

  • To make a vow; to promise. 

noun
  • A solemn promise to perform some act, or behave in a specified manner, especially a promise to live and act in accordance with the rules of a religious order. 

  • A declaration or assertion. 

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