You have my word
我向你保证
I am sorry. I don’t mean it. You have my word. I won’t do it again.
对不起，我不是成心的。我想你保证，我再也不会那样了。
The work will be finished by the end of this week. You have my word!
这项工作一定会在周末之前完成，我向你保证。

I give you my word
我向你保证
I give you my word (that) I'll go.
我向你保证，我会去的。

A: Do you think you could do me a favor with this price?
这个价格还可以再优惠点吗？
B: Oh, of course......You know, normally we retail that for $29, but since you are such a good customer of ours, we will give you a discount. How's about 3% off? That's a higher discount than I give almost all of our customers.
当然可以，你知道我们通常的零售价是29美元，既然你是我们忠实客户，我们愿意给你打折，九七折怎么样。这是几乎所有顾客中我给的最高折扣
A: Thanks! Does it come with insurance?
谢谢。含保险吗？
B: I'm sorry, I really wish I could do that for you, but our policy is to sell it without the insurance. If you would like to purchase that separately, I can give you a real deal on it.
很抱歉，我真的希望我能这么做。但我们的政策是所卖商品不带保险费，如果你想单独买商品的话，我可以给你实在的价格。
A: That's okay. I'd like to look at some of the different models.
那样也可以，我想看看其他不同的款式。
B: Oh! Yes. Take a look at this one. This is not usually available, we keep it behind the counter because it is limited edition. Of course, I know you're such a good friend, so I can let you have it at base rate.
好的，看一下这个，这是不常见到的，因为是限量版，我们藏在柜台后面，当然我们是老朋友了，所以我就卖给你最低价吧。
A: Does it have a guarantee?
有质量保证吗？
B: For you, I'll guarantee it personally! You have my word on it.
对你，我以个人名义担保！你可以相信我的话。