affair of the heart vs courtship

affair of the heart

courtship

noun
  • The behaviour exhibited by an animal to attract a mate. 

  • The act of trying to solicit a favour or support from someone. 

  • The act of wooing a person to enter into a romantic relationship or marriage; hence, the period during which a couple fall in love before their marriage. 

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