I KNOW that some journals are trustworthy
How would you KNOW a journal is trustworthy? Is it the publisher? Or the scientific Association backing it? Or the editor-in-Chief? The board? The peers who review?
I am thinking it is neither the journal nor the publisher. It is the peer-review system. And unless you know the author or the reviewers to be trustworthy and their intelligence and/or knowledge more reliable than yours, there ought not be a chain of trust. Expect there to be mistakes, bias or worse.
http://michaelnielsen.org/blog/three-myths-about-scientific-peer-review/
https://www.ncbi.nlm.nih.gov/pubmed/?term=fraud*[Title]+AND+%28scien*[Title]+OR+research*[Title]%29
http://theconversation.com/hate-the-peer-review-process-einstein-did-too-27405