1. Absolutely!/ Definitely!

那当然！

2. It's certain.

那是一定的。

3. It's for sure! / Sure thing!

那是一定的！

4. You bet! / You betcha! / You bet your life!

我可以打包票！

5. No doubt! / There's no doubt about it!

毫无疑问！

7. It's in the bag.

已经是囊中之物了。（十拿九稳、跑不掉的。）

8. It's settled. / It's set in stone.

已经定案了。

9. It's a done deal. / It's a dead cert!

已经定案了。

10. Sorted!

搞定！（英式）