I'm flattered, but I can't. It's very sweet of you though.

你过奖了，但是我办不到，无论如何你人很好。

I'm flattered that you asked, but I'm not ready to start a relationship right now.

你会这么问让我很是受宠若惊，但是我现在还没有准备谈恋爱。

A:You're the most beautiful girl in the world.

你是这个世界最美的女孩。

B:I'm flattered.

过奖了。