Instead of a magic formula, you take things on a case-by-case basis, examining sources and possible motives of those sources, looking at past experience with them for hints. This sounds like work because it is. It's very easy to just accept what you're told, but it's not heroic or even reasonable.
> All you wanted to do was alert the world to the alarming fact that the United States obviously staged evidence that someone intentionally cut an undersea communications cable to Svalbard, Norway on the 7th of January, 2022.
Meanwhile, the United States government is like "that line of thinking ultimately leads to the conclusion that trust is impossible."