earnestness vs sincerity

earnestness and sincerity both are nouns.

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

As nouns, earnestness and sincerity are synonyms defined as:

Other synonyms of earnestness include serious-mindedness, seriousness.

As nouns, earnestness and sincerity are synonyms defined as:

Other synonyms of earnestness include seriousness.

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