if not

@azz posted:

a. She said, if not that a decision in his favor had already been made, that it was definitely a sure thing.
b. She said, if not that a decision in his favor had already been made, it was definitely a sure thing.
c. She said, that if not a decision in his favor had already been made, it was definitely a sure thing.

Which of the above are grammatically correct and meaningful?

The idea is:
If she didn't say that a decision in his favor had already been made, she said that it was definitely a sure thing.
She said either that a decision in his favor had already been made, or that it was definitely a sure thing.

Would (a), (b) or (c) be acceptable in formal English?

Hi, Azz—Sentence (a), though clumsy at best, is marginally acceptable, whereas (b) is ungrammatical and (c) abominable. For the meaning you have in mind, the sentences you have used to state the meaning are much better than (a).