导购口语:

I'm sorry. I'm afraid we can not exchange it for you.
对不起，恐怕不能给您换货。
I'm sorry. I'm afraid it can not be changed.
对不起，恐怕不能够给您换货。
We could take it back and deliver a new one.
我们可以收回该产品，并送一个新的给您。

语句解析:

在I'm afraid it can not be changed.中I'm afraid...是种礼貌客气的说法，表示“恐怕……”。

情景再现:

I am afraid we can not exchange underwear for you.
对不起，恐怕不能给你换内衣。
Can I exchange it if I change my mind after purchase?
加入我买回家后改变主意，能拿过来换吗？
It shrank too much. Now it's too small to wear.
这衣服缩水缩的太厉害了，现在都小得没法穿了。
It is defective. I didn't notice it when I brought it.
这是次品，买的时候我没注意。