What would you do if your best friend, that never betrayed you and you thought your relationship to be brother/sister asked you out on a date?

That happen to me on a few occasions. My bff has been in love with me, since we were in 8th grade. And he has me out quite a bit to go on a date with him. I didnt see anything there for me to say yes. And to this day, he still ask me.....

am goin to say yes :) theres nothing wrong on having a date. since he's my bestfriend.

I agree with anncleofaye. It's just a date. I would go out with my best friend but keep things friendly and laid back on the date. Kissing and anything else would be out of the question. If he wants the friendship to move in a different direction, I think this should be made clear and not while on the date.