Is it possible to be best フレンズ with the opposite sex without anything romantic going on または one of them being gay?

Of course! Although, it's very rare in my opinion. During younger years, like in highschool (yes, still very young), some girls may find themselves closer to guys (that's me), but as we continue to develop and mature, the differences starts to set in and often the friendship will slowly fade. Two can still be friends, but being 'best friends'- meaning the complete understanding, the ability to sympathise and full support no matter what- becomes challenging due to the differences in cognitive processes and behaviours in general. It's difficult to maintain a mutual, really close friendship (that last long) between opposite sexes without turning out to be a romantic one または one of them being homosexual. When you're THAT close to somebody, there will be attraction as being best フレンズ also mean that あなた appreciate each other, accept them for who they are and cast no judgments- which overlaps with some of the foundations of a solid romantic relationship.
It can happen, but can't think of any particular example atm...

But then again, two best フレンズ falling in 愛 is pretty awesome since they both understand each other almost completely, so あなた usually get quite successful romantic relationships. As for homosexuals, it eliminates the awkwardness that can arise between two フレンズ and so that makes a really strong friendship.

Of course it is possible.

Yes, of course it is. I personally think it's rare but I've been in that position before many of times actually.

Not according to my brother, if あなた asked him, I've got about five different boyfriends atm. If あなた ask me then I have none. Go figure.

Idk, I was just フレンズ with one if my フレンズ that is a boy, and I'm a girl, I thought nothing romantic was going on until yesterday when he told me he was going to ask me out at the beginning of the 年 (when we met)

i hve not been in the sution on hs but i hve been with oppsite sex bestfriends and i hve dated my best guy friend(but now his just a jerk)but now i hve new best guy friend(but we hve not romatice conction)but i do believe that there can be bestoppsite sex friendship that can go to the 次 leavle

Yes it is

Of course it is! many of my mothers フレンズ are guys, and so are most of mine :)

Absolutely! I'm best フレンズ with some boys, and it's all platonic. I suppose it is rare, though.