For a minute she stood looking down at him doubtfully.

She was unable to understand the actions of this new variety of book agent that refused to sell books after talking up to the selling point, and she suddenly remembered that she was away from home, and that the book was sold on installments.

She flushed.

Did his refusal to sell imply that she might not be able to pay the installments?
"I'll take a copy of that book, IF you please," she said haughtily.
"I guess there ain't no question but that I'm able to PAY for it.

I've bought books before, and paid for them; and I guess I'm just as able to pay as most folks you sell to.