Internet dating

I struggle pretty bad with anxiety so I find the best way to meet guys is online... I can't pick up in bars or just approach a guy :( 
I have no shortage of guys wanting to meet but my main problem is... How do I tell the genuine ones from the ones who are just gonna play me? I've met several guys who have said they aren't just in it for sex and then just seem to use me for sex... I need help!!