Honestly, ANY site - darknet or clearweb - is just as trustworthy as any plasce that isn't within arm's reach.
Anywhere that someone can make a quick buck by stiffing other people, regardless of whether it ends in .onion, .net, .com or .Ilooklikethehamburglar will be used by such people to do the most stupid and most heinous scams.
The fault lies not with any part of the internet, the fault lies with people being scumbags.
If that wasn't the case, then there'd be no "scam accusation" subforum on any site on a .org domain.