trust means nothing, and if you are honest you can do your business (sells) on the forum even with a brand new account. as Rockie1234 explained what an escrow is, you use one for every trade you make no matter if you have 0 trust or green trust. that way there is never any problem (well to be exact there is always a small risk like escrow running away but that is nothing to worry about)
And it goes the other way, too. Look at my trust page and you'll see the dozens and dozens of people who've left me negatives, and I've done business with ZERO of them. Some of them make pretty specific claims about very specific amounts of bitcoin--and they're all lies. All of my red feedback is retaliatory for negs I've left account dealers. My positive feedback (except for Vod's and cpfreeplz's) are from people I've actually done deals with.
But I definitely agree about not trusting people with green trust. I learned that the hard way with Timsweat. There are definitely users I trust and that I would send bitcoin to first. Few of them, but they do exist. You're going to have to figure it out for yourself, though. I hope your tuition isn't as expensive as mine was and a lot of people here's was.