What is what does it mean when a girl calls you bestie?

When a girl calls you "bestie," it usually means that she values you as a close friend and considers you to be someone she trusts and can confide in. It's a term of endearment and affection that implies a strong emotional bond between two people. However, it's important to note that every individual may have a different interpretation of the term depending on their personal relationship with the other person, and it is not necessarily a guarantee of any romantic interest.