@ificouldreturnit,
I don't know all the technical names of tenses, so you can ask somebody who knows, or who wants to look it up. But, that said, I would probably just say:
Quote:Tom: I knew you would help him
It's not clear from this
when Tom said this, i.e., before or after the help had been given. Let's say it was after. Let's say "you" is Bill, and "him" is Joe.
Tom said he knew you Bill would help him Joe.
Or, maybe: Tom told Frank that he knew Bill would help Joe.
Just because it was said in the past does not mean you have to make everything past tense. You can report it as though it is contemporaneously happening, i.e. as though you were at the scene at the time and are repeating what was said at the time.