The word "ain't" is a very informal versions of: am not, are not, is not, have not, has not, do not, does not, did not So basically equivalent to 没有 in Chinese. It is more commonly used in speaking rather than writing. "If it ain't broke, don't fix it." A common saying in English. =)

wanna gonna gotta ain't 黑人街区的RAP或HIP-POP歌手最喜欢用这些文盲英语