graveness vs sincerity

graveness and sincerity both are nouns.

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

As nouns, sincerity is a hypernym of graveness; that is, sincerity is a word with a broader meaning than graveness:

Other hypernyms of graveness include earnestness, serious-mindedness, seriousness.

graveness (noun)	sincerity (noun)
a manner that is serious and solemn	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