plight one’s troth vs settle down

plight one’s troth

settle down

verb
  • To get comfortable with one's new accommodation or circumstances. 

  • To become quiet and calm after a period of disturbance or restlessness. 

  • To establish a settled lifestyle, and especially to marry. 

How often have the words plight one’s troth and settle down occurred in a corpus of books? (source: Google Ngram Viewer )