ambivalent vs unsure

ambivalent

adj
  • Simultaneously experiencing or expressing opposing or contradictory feelings, beliefs, or motivations. 

  • Alternately having one opinion or feeling, and then the opposite. 

unsure

adj
  • unstable or precarious 

  • uncertain 

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