Not very I'd imagine. Here mother is white and her father (I think she said she does not speak to him on the Baba Wawa show) is black.
To see Halle at her "best", see the movie BAPS (Black American Princesses). Her and another black actress basically reprise the roles of Amos & Andy:
Berry plays what's basically a stupid black girl with bad clothes, bad hair, bad teeth and bad diction. The role was awful and racist. The supporting cast included a couple of young black men that were characterized as just a stupid and shuffling. The screenplay could have been written by David Duke.
But, she is an "actress" so I suppose she can play a black female. Maybe being half-black helps?