ambivalence vs vacillation

ambivalence

noun
  • A state of uncertainty or indecisiveness. 

  • The coexistence of opposing attitudes or feelings (such as love and hate) towards a person, object or idea. 

vacillation

noun
  • Indecision in speech or action. 

  • Changing location by moving back and forth. 

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