"What are you talking about, Kafka?...There's no way that makes any sense."
Nina didn't have an exaggerated reaction like Kafka thought she would, and she calmly stated while looking at him as if she were asking him if he were crazy.
It's not that she didn't want to scream or shout at what he said, but because the proportion of absurdity in the statement he had just uttered was too much, her mind simply short-circuited whilst she stared at Kafka with a look of confusion written all over her face.
"I mean, to say that I want to have your children, just because I said that I want you to do something rather dirty to me...Isn't that a bit too nonsensical to believe and a simple attempt at a joke from you?"
Nina chuckled, hoping Kafka would also laugh with her and say it's a joke.