I promise I'll keep the secret.

我发誓我会保守秘密的。

You cannot tell anybody else.
你不可以告诉别人。
I promise I'll keep the secret.
我发誓我会保守秘密的。
I swear to keep it a secret.
我发誓会保守这个秘密。
Can you keep a secret?
你能保密吗？
I would appreciate your keeping it a secret.
你能保守秘密，我非常成谢。
I believe that you can do it!

我相信你一定能做到!

I believe that you can do it!
我相信你一定能做到！
Thank you. So do I.
谢谢。我也这么想的。
I know you'll make it, if you try.
我知道如果肯尝试，你一定能做到。