"He is a guerrillero from the other side of the lines with a dispatch of the utmost importance for the General Golz who commands the attack that is to be made at dawn beyond Navacerrada," Gomez said excitedly and earnestly.
There are no more uses of "earnest" in the book.
Show samples from other sources
Both sides were deeply in earnest, even passionate.
She has a casual, go-with-the-flow personality and doesn’t appreciate his earnestness.