sincerity vs sincere

sincerity is a noun but sincere is not a noun.

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

sincerity (noun)	sincere (noun)
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

sincerity (adjective)	sincere (adjective)
	open and genuine; not deceitful
	characterized by a firm and humorless belief in the validity of your opinions