导购口语:

We guarantee the quality of the product we sold.
我们所售的货物，保证质量。
Regardless of the cause of the trouble, all repairs are guaranteed within three days.
不管是什么原因的故障，所有的修理包正在三天内解决。
If something goes wrong with the air conditioner, you can bring it here and we’ll send it to the manufacturer.
如果空调有设么问题的话，您可以拿过来，我们将它送到生产厂家去。

语句解析:

Guarantee the quality of the product保证质量；regardless of不管；within three days三天之内。

情景再现:

Goods purchased in our factory can be changed within a month, but we don’t exchange any item that is improperly used or damaged by the customer himself.
凡在我厂购买的商品，一个月内可调换，但对由于顾客自身使用不当造成的损失，不承担责任。
We guarantee the quality of the product we sold in our store for one year.
我们店卖出的商品在1年内保证质量。