I find the following sentence in need for the "Sooner or later" but in its negative form.
This is what I don't intend in disclosing. Not sooner or later.
The speaker wants to emphasize on his refusal of disclosing an X matter. I don't find "Sooner or later" fits the sentence, with preserving the speaker's technique of stating that.
But it may fit if the structure of the sentence changed a bit, like:
This is what I don't intend in disclosing sooner or later.
According to Collins Dictionary:
If you say that something will happen sooner or later, you mean that it will happen at some time in the future, even though it might take a long time.
Sooner or later she would be caught by the police.
In my case, the speaker is certain that that won't happen in the future. So, is there a negative form of the phrase? Since I didn't find it stated on the Internet in its negation. Google Search - Google Books