My best friend has been stealing off of me! What should I do?

dump her. she obv has a problem. u r worried money will be next. personally id be more concerned she took something sentimental such as your grandmas ring. if you ever catch her red handed get the police involved and dont think about what other people will think coz she aint gona go round telling everyone what she done to deserve it is she? maybe she is jelous of your possessions or likes the idea of money hence selling your stuff. try talking to her first.