solemness vs earnestness

solemness and earnestness both are nouns.

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

As nouns, earnestness is a hypernym of solemness; that is, earnestness is a word with a broader meaning than solemness:

Other hypernyms of solemness include serious-mindedness, seriousness, sincerity.

solemness (noun)	earnestness (noun)
a trait of dignified seriousness	the trait of being serious
	an earnest and sincere feeling