We CAN trust what has been written......but we CAN'T trust that someone "saying" ie writing something is coming from the Holy Spirit. You are NOT making sense.I believe this verse supports that view:
John 21:25 And there are also many other things which Jesus did, the which if they should be written every one, I suppose that even the world itself would not contain the books that should be written.
I also believe we can trust what has been written and we can't always be sure that someone saying something is coming from the Holy Spirit is not self deceived.
You are saying that writing is to be trusted but talking isn't to be trusted.