It is a rather childlish example.It depends on the context, but
え～、知りたいの～？？ might be the candidates of sarcasm as Vaan mentioned.
知りたい？It is just a simple, curiousity, like a Japanese girl asked me of my country's culture, for example Malaysia's food. That's all. マレーシアの主食って何ですか？
I simply reply, rice.