You can't. It depends on how they see you and the relationship and even if they tell you it is so, you have no way of knowing if it is true. Sadly, most people lie about things like this and only time will tell. All you can do is be the best friend to them that you know how to be and see what develops. It doesn't have to be a two way street or equal both ways. You might be a great friend to someone and they treat you like dirt. That's on them. You acted as well as you could and if they don't respond in kind, it's their loss.
What you can do is always stand up for your friend, give them presents to show that your really their best friend.
Because my best friend is not my best friend anymore and i am REALLY REALLY REALLY upset :( :( :(
if you want him to trust you tell him somthing you wouldn't even tell your best friend
Be there for them
a really really good best friend
On the tv show "Mad About You" Jamie's best friend is Fran Devanow, earlier in the show they worked tpgether but as the show progress they do not.
not really
His best friend was Keely (Alyson Michalka.)
Go to Queenpspk . She will be your best friend. She's really nice.
Find a new best friend.
If that person really is your best friend, telling him/her what's happening should straighten things out. Maybe not immediately, as some hard feelings may show themselves or he/she may need practice.
It can be because he either likes your best friend or he likes you but he either doesn't show it, pretend, or make you jealous to show a sign. Give him away to your best friend or impress him in your own way of doing it.