Verified answer

you cant

if they replied,

you will be sent a notification saying "_______ Has accepted your friend request"

it doesn't say if they denied your friend request, but if you searched their name, it'll either say "Friend Request" And if you already friend requested, that means they denied. If it says "Pending Request" that means they haven't answered yet .

(: have a good day.. or night .

the only way to tell is if you try and request friendship and you already have it will say friendship pending if you dont see that message then the person declined !