Source : Webster's Revised Unabridged Dictionary (1913)

Assuredness \As*sur"ed*ness\, n.
   The state of being assured; certainty; full confidence.

Source : WordNet®

assuredness
     n : great coolness and composure under strain; "keep your cool"
         [syn: {aplomb}, {cool}, {poise}, {sang-froid}]