Earnestness
Etymology
From Old English "eornost" (seriousness, zeal, earnestness), related to German "Ernst" (seriousness). The word has always named committed gravity of purpose; Wilde’s pun in "The Importance of Being Earnest" plays the virtue of earnestness against the name Ernest. In an ironic age, earnestness carries a faint risk of seeming naïve — which is itself telling about the culture.
noun · /UR-nist-nuhs/
Sincere and serious intentness of purpose, free of irony or frivolity.
What it names
Use it for wholehearted seriousness — meaning it, and showing that you mean it, with no protective layer of detachment or joke.
Example
The volunteers’ earnestness was disarming; no one was performing, they simply cared.
Related idea
Sincerity is about truthfulness — that you mean what you say; earnestness adds intensity and gravity — that you mean it deeply and without irony. One can be sincerely casual, but earnestness is never casual.
See also