Your nonna!

I guess it depends on what we're talking about:
If it's about trusting one's memory then sure, better to make sure and check the accuracy with some sort of external source.
If it's about not trusting one's own judgement when sleepy, anxious, horny, furious, under the influence of substances, having a panic attack, etc. Then it's just better to wait until one's back at whatever passes for normal or baseline before making any important decision.
Now if we're talking about serious mental disorders like hearing voices, visual hallucinations, or fake memories. I'd suggest looking for professional help. But I've heard that some people that struggle to tell what's real and what's just in their head use their phones to record whatever they're seeing, since if it isn't real it's not gonna show up on the screen, same goes for recording audio.

No one. Be wary I guess ._.

Fitting song if you don't mind roars. Because that means you don't really have to trust and define yourself with negatives either.

It's good to trust your brain. But the brain can only work under calm conditions. If you are overcome with strong emotions, those will cloud your judgement. Or if you drink alcohol, you blind your brain from working. So if you are somehow aware you are in these states, it's best to take a step back to think things more calmly.

Bump for solved!

Learn from your personal experience and trust this, that most often gives you the right answers/hints. And so in my case, though I highly value my mind and my analytical skills, at the very end the crucial decisions most often I do base on my intuition, because whatever the mind says, my intuition is almost always right. That's though, my personal case, for you this may be quite the opposite.

Maybe your brain in da past, by like having a diary on and seeing ur own perspective on some issues and such and/or well.. trusting someone else's(who u find smarter or like more experienced in the matter) brain but that's kinda a judgment u make with ur own brain and as such doesn't really fit in the whole not trusting your own brain thingy entirely and also Imo it's not that u shouldn't trust ur brain ever but more like having a doubt always on what your brain tells u and actively trying to seek new perspectives on the matter, ones u don't even maybe agree with on a basic lvl and looking at them with no prejudice and trying to see the angle that the ppl who have those ideas are coming from, that way while ur still doing as your brain tells u , u r reducing the pitholes that one might fall into when so very much is trusting of their own brain thingy .in the end I doubt its a good idea to trusting anyone else fully as their brain is well kinda fallible like urs and when stuff goes forky , u don't know what to do or how to react or fix the situation sooooo like the best one can do is to just to uh expand one's own perspective and uh be open to other brain's ideas on stuff they might be better at lol.

p.s. sorry if its incoherent and forky or not helpful much , I'm a bit potatobrained at the moment(as always) lol

Thanks for Skyrim! Trust no one. Check. めんどくさい。障害ない。Going always for the gut feeling can get your hefty rewarded....or in big trouble.

View attached image.

Also, this too.

if it's good not to always trust my brain, whom i should trust, then??

trust me bro