How do you know if your friend is really a true friend?

okay today my ex-best friend lost 15.00 or someone stole it and she thought it was me i quess she diddnt really say it but,actions speak louder than words so then i went to the locker to get her computer in her bag and i took 50 cents out her bag and i swear that was all that was in there and so she has another friend that share lockers with us and they think it was all my faught because i took 50 freaky cents and i do think that sounds guilty but still she should of known i wouldnt do any thing like that and we been knowing each other for 4 yrs she shouldnt even be acting the way shes actin and now her other friends are actin the same twords me even the f*ckin teachers,! so tell me should i talk to her or just let her go her way and ill go mines