How to know if he is serious or not

Hi there, the description of my question goes here as this. I met this guy few weeks ago online and we keep chatting everyday. Seems like he is interested bec we chat everyday and sometimes it goes so funny. But the problem is that he got my number and told that he will call me but he hasn't. No invites to meet up even. It has been nearly three weeks we started to chat and I want to be clear whether he is interested in me or not. In other words, will he be worth for a sustainable relationship? Because I am so panicked about the players around the world and I have also heard about sociopath people who take advantage of others. In fact, I dont want to waste my time with players. I know a relationship takes a long time to establish. But shouldn't the intuition know that it wil go well in the beginning point? I am bit odd to ask it directly from him but is there anyway to check/test if he is serious about me? Any advises welcome...Pls share your ideas..Thanks a lot in advance.