"You smell of the countryside" in this case is such a nothingburger insult? Its a very child-like thing to say in an attempt to hurt someone. Because the second you think about it logically, the argument breaks apart. They're both living in Nagoya. That's quite literally one of the farthest reaches a big city can be away from Tokyo. So her saying this is so ineffectual its like pot calling kettle black, except the kettle actually lived in the capital, unlike the pot.