Carley had a positive belief that he would not do it for her.
And after Flo's repeated efforts, assisted by chastisement from Glenn, had kept Spillbeans in a trot for a couple of miles Carley began to discover that the trotting of a horse was the most uncomfortable motion possible to imagine.

It grew worse.

It became painful.

It gradually got unendurable.

But pride made Carley endure it until suddenly she thought she had been stabbed in the side.