All 8 Uses

earnest
in
The Railway Children
(Edited)

'We mustn't think of the garden yet,' said Roberta, with earnest energy.
p. 25.8

earnest = sincere or serious
She dried her eyes and sniffed earnestly.
p. 81.2

earnestly = sincerely or seriously
So she just loved Mother more and never said a single word that could let Mother know how earnestly her little girl wondered what Mother was unhappy about.
p. 122.8
No, no, said Bobbie, earnestly.
p. 135.2
All eyes were intent on the sluggish waters that earnestly pretended they had never harboured a single minnow when a loud, rough shout made them start.
p. 146.4
'Yes, we will; indeed we will,' said Bobbie, earnestly; 'but we do beg your pardon — and really we haven't caught a single fish.
p. 148.8 *

earnestly = sincerely
'There are always flowers, of course,' said Bobbie, later, when a really earnest council was being held on the subject in the hay-loft where the broken chaff-cutting machine was, and the row of holes to drop hay through in to the hay-racks over the mangers of the stables below.
p. 161.7

earnest = sincere or serious
Bobbie burned the feathers of the shuttlecock one by one under his nose, Phyllis splashed warmish milk on his forehead, and all three kept on saying as fast and as earnest as they could: 'Oh, look up, speak to me!'
p. 218.9

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).