at ease vs self-assured

at ease

prep
  • Allowed to refrain from being in rigid formation. 

  • Free of anxiety; not stressed or tense. 

  • In a relaxed position with the feet apart rather than at attention. 

self-assured

adj
  • confident in one's own abilities 

How often have the words at ease and self-assured occurred in a corpus of books? (source: Google Ngram Viewer )