There is no doubt that he will keep his promise and I am sure that he will do what he said.

毫无疑问，他会信守诺言，我相信他会言行一致。

youdao

I wonder if he will keep his promise.

我想知道他是否会遵守他的诺言。

youdao

Promise is very important, I hate people who break their promise, the one who can't keep his promise is not reliable.

诺言是很重要的，我讨厌那些不遵守诺言的人，谁不能遵守他们的诺言，谁就不可靠。

youdao

Second, I sincerely doubt that Bernanke will be able to keep his promise to control inflation quickly once he finally admits it has arrived.

FORBES: An "All-In" Bet By Fed Chairman Ben Bernanke