Generally speaking men and women can't be friends. One will have an attraction for the other or both will but for whatever reason they don't want to admit it to themselves so date other people, which is in my opinion rather annoying and wasting other peoples time. If just one has the attraction it is usually the male, who will be thinking with his balls more than anything else, and at some point the friendship will be down the toilet because he will either make moves on her and they won't be returned, or he will get so bitter at the sight of her sexual conquests he will just move away . This male will usually declare himself a 'nice guy', when he is anything but, he is no better than the dudes who were actually successful in getting in her pants.
Women naively think men want to be friends with them,no these men want to fukk you, you aren't that interesting believe me. The best ones are the men who claim they are 'bi' or 'gay', but somehow end up fukking their female friends, because said female friends saw them as a 'challenge' or 'non threatening' so their guard goes down , so if you start dating a female with a 'gay' best friend, don't just guard your ass, watch him around your girlfriend. I would actually trust a female with a lesbian best friend more than a gay male best friend, because men will fukk mostly anything if they are given the opportunity.