soberness vs earnestness

soberness and earnestness both are nouns.

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

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

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

soberness (noun)	earnestness (noun)
a manner that is serious and solemn	the trait of being serious
the state of being sober and not intoxicated by alcohol	an earnest and sincere feeling