serious-mindedness vs sincerity

serious-mindedness and sincerity both are nouns.

Word	Noun	Adjective	Verb	Adverb
serious-mindedness	Yes	No	No	No
sincerity	Yes	No	No	No

As nouns, serious-mindedness and sincerity are synonyms defined as:

Other synonyms of serious-mindedness include earnestness, seriousness.

serious-mindedness (noun)	sincerity (noun)
the trait of being serious	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