A person that will always be there for you. Someone hat is a like a sister or brother to you.

Your Person. Your # 1.

Forever.

Someone who has been through the worst with you, someone you love unconditionally, no matter how much you fight. A bestie is something better than a friend, she is part of you, never let let go of your bestie, and she will never let go of you.
Smooches

Kind of like your best friend, except better.

A person who knows you better than any one else. When you insult them they just laugh and come up with something even more offensive then what you said. A bestie has 500 pictures of you, you hope no one will ever see. They know what makes you happy and what makes you sad, they can tell right away if something is wrong. they can say you are weird, stupid, idiotic, etc. and you can just laugh.

your best homie

A bestie is someone you're very close to and you share a deep passion with. Besties tell each other everything and do not have any romantic relationships with each other. Some besties even have a hand shake and all besties have many inside jokes. Besties are often of opposite genders.