calmness vs assuredness

calmness and assuredness both are nouns.

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

As nouns, assuredness is a hyponym of calmness; that is, assuredness is a word with a more specific, narrower meaning than calmness:

Other hyponyms of calmness include aplomb, cool, poise, sang-froid, placidity, quiet, repose, serenity, tranquility, tranquillity.

calmness (noun)	assuredness (noun)
steadiness of mind under stress	great coolness and composure under strain
a feeling of calm; an absence of agitation or excitement
an absence of strong winds or rain