unassumingness vs sincerity

unassumingness and sincerity both are nouns.

Word	Noun	Adjective	Verb	Adverb
unassumingness	Yes	No	No	No
sincerity	Yes	No	No	No

As nouns, unassumingness and sincerity are synonyms defined as:

unassumingness (noun)	sincerity (noun)
a quality of naturalness and simplicity	the quality of being open and truthful; not deceitful or hypocritical
	the trait of being serious
	a quality of naturalness and simplicity
	an earnest and sincere feeling