How do you know if your best friend actully does like your crush, eventhough she sid she didn't?

ok, at a end of the year party w/ my friends, my best friend Mia, was flirting like crazy with my crush... she told me earlier that she doesn't like him at all and she knows that i really like him! the wierd thing was, that when i came to the party he said my name and smiled, and his best friend stood up and gave me a hug. from that momet on she wouldn't stop flirting and my crush wouldn't stop responding to her! Do you think that she really likes him or is jealous of me or something?How do you know if your best friend actully does like your crush, eventhough she sid she didn't?
she your best friend! you need to trust her. she may just be being friendly.... boys come and go friends are forvever...