What should i do if the guy i like likes my best friend?

im a very honest person if she told me this i would b like "STFU! YA BI***! u kne i liked him, solve ur own damn poroblems ya h**." but since ur probably nicer abou it id jst grin and bear it. but he wouldnt hav askd her out if she wasnt OBVIOUSLY flirting with him! ive been in this situation. its best to cut ties with both.