Nǐ zěnme huì zhèyang xiǎng?

你怎么会这样想?

How could you think that?

Notes:

你(nǐ): you

怎么(zěnme): how

会(huì): can

这样(zhèyang): so, (to do something) like this

想(xiǎng): to think

Example:

A: 是不是你拿了我的钱?

    Shìbushì nǐ ná le wǒ de qián?

    You took my money, didn't you?

B: 你怎么会这样想？

    Nǐ zěnme huì zhèyang xiǎng?

    How could you think that?