The Collaborative International Dictionary of English v.0.48:
Assuredness \As*sur"ed*ness\, n. The state of being assured; certainty; full confidence. [1913 Webster]WordNet (r) 3.0 (2006):
assuredness n 1: great coolness and composure under strain; "keep your cool" [syn: aplomb, assuredness, cool, poise, sang- froid]