Difference between "isn't" and "ain't" [closed]

Solution 1:

In American English, "isn't" is the standard contraction of "is not," and "ain't" is a nonstandard, dialectal contraction of "is not" and and sometimes "are not" and "am not" (He ain't, They ain't, You ain't, I ain't). In the U.S., it's most common in Southern speech, but it wouldn't be accepted in formal writing in any region unless the writer was quoting someone or deliberately striving for a vernacular tone.

Solution 2:

"Isn't" is a contraction of "is not".

"Ain't" is a vernacular expression of "isn't", and although it carries the equivalent meaning, it is not part of Standard English.