I want to ask my new neighbor if she adopted african kids
Why do you want to ask your new neighbor that?
I have seen she has black kids and I hate blacks.
Aside being a terrible and racist thing to say, you are invading their privacy. You should make your new neighbor feel welcome, not like an outcast.
Maybe I should respect her private life a little more.
I think that would be best, just keep out of their business. Maybe you could educate your self on African American culture and open your eyes on the subject to be less predjeuice.