How can I approach this guy?

So, I have zero romantic/dating experience and there's a guy that I think is cute and he has sparked some interest in me, but I'm not sure whether he's gay or bi or straight. He doesn't look completely straight nor gay, so I don't know what to do in that scenario.Also he knows I stare at him. He has caught me looking at him a lot of times and he has glimpsed at me a couple of times too, but he might have done that because I did it first. That's not enough proof nor encourage for me to be a little more sure that I might might get some positive feedback. The last time I tried to approached someone he humiliated me, played with me and dismissed me, so I am scared that situation happens to me again and, like I said before, I don't know how to approach people that I feel a little attraction to.I really need some advice on how to approach him please. I want to talk to him soon because I'm really good at fantasizing and that ends up being completely detrimental for me. Thanks for reading.PD: I am not a native english speaker so I'm sorry if I made some grammatical or orthographic error.