How do you tell when a guys interested or just curious?

[Anonymous]

If your best friends bro asks you if you have a boyfriend and he's been "wondering for a while now", does that mean he's interested or just curious?
I was just hanging out with him when he randomly asked me, we don't usually talk about such personal things so now I'm confused. I've had a crush on him for a while now so I don't know if I'm seeing things that aren't there :(

[xxxuknownxxx]

interested would stay for ever until you give him the red light
Curious will ask couple questions or know something just leave.