"I have a pretty good guess. I'll put in another dollar."

It could be significant that he's not wagering another two dollars, like he had before, but it could also be an attempt to throw her off, to make her think that his hand is worse than it actually is. "And since you said you wanted to see it through to the end, you can toss your dollar on in there, too. Unless, of course, you want to raise."

He's already preparing to deal the final hand, confident that she might match the dollar he put in, but definitely won't increase the wager.