principled vs truthful

principled

adj
  • strongly adhering to, or heedful of, guiding beliefs or moral rules 

  • Based on, having, or manifesting principles 

truthful

adj
  • Honest, and always telling the truth. 

  • Accurately depicting what is real. 

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