All 4 Uses

earnest
in
Seventeenth Summer
(Auto-generated)

Jack was sprawled on the grass, talking very fast and earnestly, his eyebrows knit together.†
Chpt July *

earnestly = sincerely or seriously
His forehead was puckered up with earnestness.†
Chpt July

earnestness = sincerity or seriousness
Jack's voice was very earnest as he explained, as if he wanted to convince me that it was necessary to move, that it wasn't his idea, but I could tell he was just repeating what he had heard at home.†
Chpt Augu

earnest = sincere or serious
His voice was earnest now.†
Chpt Augu

Definitions:

(1) (earnest)
characterized by sincere belief

or:

intensely or excessively serious or determined
(2) (meaning too rare to warrant focus)
Earnest can also be used as a name (variant spelling of Ernest), or to signify the seriousness of a pledge made (as when earnest money is included with an offer to purchase a home).