So when I go to a betting site I prefer three main things: Trustworthiness, timely and efficient deposits/cashouts, and good support.
Trustworthiness is a major thing for me because I don't want to deposit and have them run off with my money. I would want the platform to receive my money and have it ready for me to play by one or two confirmations(standard protections against double spends which I don't mind), and if there are any problems a good support should be able to help me fix them(or try to fix them) with decently fast response times(or at least a live chat but that isn't really something I worry about too much, long as it doesn't take a week or something to respond or something then I'm fine with a couple hours/a day). I don't really mind KYC but I would prefer to not send it over.
How would you know if a site is trustworthy by looking at it?
Since this is also one of the factors I'm looking to, I'll just say my opinion... You can know at some point if a site is trusth worthy by the reviews of the players and the users gave. Insights and reviews should also be available where you can also ask or tell your problems and issue regarding the site and see how responsive the site is. It's also a good way for you to maintain its image and trust.