The interviewer is dissatisfied by Geralt's final answer.

Since Geralt has admitted to the crime, the city guards will take over. He'll be held in the Cadens jail for about 24 hours before they determine his penalty to be an additional day confined and a large fine...mostly to cover the labor cost of cleaning up the scene he left. If he can't afford the fine, he may "pay" it by serving an additional 3 days.

A harsher penalty may result if he resists.