One of my best mates seems to slightly like a girl. Other friends encourage him to go for this girl but he doesn't seem overly interested in pursuing anything with this girl. There's a chance he doesn't even like her in that way. BUT she keeps messaging me and have a feeling she likes me. I'm not overly interested in the girl but if I get the chance I could take it further with her. Would this be betraying my friend or damage our friendship? (he's one of my top 3 mates)