While jealousy is a proof of True love, it could still not be, reason being that a girl might be jealous of you but still don't love you.

She might just be jealous of you because she doesn't want you sharing your attention (as her bestie) with other girls.

This holds to be true as there's this issue of jealousy and proving pointless points especially with the ladies.

So a lady might not be interested in a guy but (on the grounds of ordinary friendship) might just not want him to be friends with...