He seemed so much in earnest that the dwarves at last did as he said, though they delayed shutting the door-it seemed a desperate plan, for no one knew whether or how they could get it open again from the inside, and the thought of being shut in a place from which the only way out led through the dragon’s lair was not one they liked.
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.