soon-to-be vs would-be

soon-to-be

adj
  • Planned or destined to have a specified position or quality in the near future. 

would-be

adj
  • Attempting or desiring something. 

  • Unfulfilled; frustrated in realizing a goal, ambition, etc. 

noun
  • One who aspires to something. 

  • One's fiancé or fiancée. 

How often have the words soon-to-be and would-be occurred in a corpus of books? (source: Google Ngram Viewer )