I guess its hard to tell if anyone is really good, male or female. The type of clothes someone wears, their attitude etc doesn't necessarily mean anything because its just aspects that make them comfortable as individuals. Whether they are good? Thats something that can only be discovered after getting to know someone personally. I know so many people who seem lovely but are always talking horribly about friends behind their backs. People always put on a mask of kindness and innocence, its hard to tell if anyone is being genuine. Clothes, style of walk, attitude etc... These are usually just parts of a made up identity, like a disguise. I always act confident and try my best to look cool but only the people close to me know that I'm actually quite sensitive and quiet. I only act confident because I don't want people to realise I'm pretty anxious, everyone wants to appear a certain way and everyone makes up their own personas to make good impressions. So to tell if a good girl is really a good girl? Get to know her. Don't judge on initial prejudices like what she wears and how walks, get to know her and slowly build an impression of her true character when she feels comfortable enough around you to show you her complete and true self.