As others have said, the sentence is equivalent to the standard English sentence "She is not an actress." This sort of negation is called "negative concord." The negative words work together to make a single negation. As has also been said, most speakers of standard English would understand the intended meaning, because we have had much exposure to nonstandard dialects which use negative concord.Just heard the song that was singing
"She aint no actress."
I know this is not a correct sentence as a formal English.
But, what is this mean?
She is an actress?