assuredness vs aplomb

assuredness and aplomb both are nouns.

Word	Noun	Adjective	Verb	Adverb
assuredness	Yes	No	No	No
aplomb	Yes	No	No	No

As nouns, assuredness and aplomb are synonyms defined as:

Other synonyms of assuredness include cool, poise, sang-froid.

assuredness (noun)	aplomb (noun)
great coolness and composure under strain	great coolness and composure under strain