Wittgenstein’s last work, On Certainty, is a meandering examination of how we come to be certain about things. In it, he writes, “[I do philosophy now like an old woman who is always mislaying something and having to look for it again: now her spectacles, now her keys.]” That certainly speaks to the wandering nature of the book.
But he also makes this more substantial point:
Certainty is as it were a tone of voice in which one declares how things are, but one does not infer from the tone of voice that one is justified.
One can say “He believes it, but it isn’t so”, but not “He knows it, but it isn’t so”. Does this stem from the difference between the mental states of belief and knowledge? No.—One may for example call “mental state” what is expressed by tone of voice in speaking, by gestures etc. It would thus be possible to speak of a mental state of conviction, and that may be the same whether it is knowledge or false belief.
In our public sphere, there are far too many people who state their disingenuously-held views with that tone of certainty. The people who spread this disinformation with their authority are far worse than those who are convinced by their lies and state them with honest conviction.
But it’s difficult to tell those two types apart.