Simply means yeabitch, but is so commonly combined into one word that is has become commonplace slang. Commonly used by girls with their friends, and boyfriends with girlfriends in a non-offensive way.
Girl: Will you take me out to the movies friday and we can go to the party?
yeabin is a girl who loves to be around her friends. she can be crazy and she loves salad. she makes a great girlfriend and is always caring and passionate. she would never let you down. yeabin is a fun person to be around always. you would never want to lose a yeabin.
Wow Jenny, lately you have been so smart! Do you have Yehahidnosisoisdishehjenamosislerimilyehailemyehahidnosisoisdishehjenamosislerimilyehailemyitis or something?