You shouldn't, it's a douche move. They are your best friend and taking a girl from them betrays their trust. If they break up then maybe 6 months to a year later (depending on the break up and how close you and your friend are) then ask if it's cool that you date her. This is if you don't want to ruin your friendship.
girl friend is a friend that is girl and not a best friend and girl friend is best friend
I'll satisfy my best friend that girl is not for you and girl is interested in me.
This means that of the girls he/she hangs around, you are the best of them. This is not to be mistakened with "girl friend". But a girl, that's a good friend.
"Who's your best friend?"
The Girl of My Best Friend was created on 1960-04-03.
Demons Are a Girl's Best Friend was created in 1996.
My Best Friend's Girl - novel - was created in 2006.
Girl's Best Friend was created on 1999-10-19.
My Best Friend's Girl was released on 09/19/2008.
The Production Budget for My Best Friend's Girl was $20,000,000.
Diamonds Are a Girl's Best Friend was created in 1949.
then good for you. that's not all too uncommon. thats really good! i am a girl and my best friend is a boy! your lucky to have a girl as a best friend...