The most beautiful irony in the story comes through the imagery. The American and Jig are discussing an abortion. When Jig gets up from the table to look out over the landscape, all she sees are images of fertility: green trees, a flowing river, fields of grain. However, she turns from this image to return to the man, having lost the will to fight for her unborn child. Here is the fertile passage:
The girl stood up and walked to the end of the station. Across, on the other side, were fields of grain and trees along the banks of the Ebro. Far away, beyond the river, were mountains. The shadow of a cloud moved across the field of grain and she saw the river through the trees.
The other irony comes in the man's argument with the woman. He spends his time telling her how simple it will be and how it is the best thing - he clearly wants her to have the abortion. However, as soon as she says that she'll do it for him, he backs up, saying he doesn't really care, he just wants what is best:
'You've got to realize,' he said, ' that I don't want you to do it if you don't want to. I'm perfectly willing to go through with it if it means anything to you.'
He clearly wants her to decide to have the abortion, but doesn't want to be seen as having made the decision himself.