Her name is Nikki.
3 seconds sound clip from the Kill Bill: Volume 1 movie soundboard.
You can hear this line at 00:08:34 in the Blu-ray version of the movie.
Quote context
[...]
- Baby, now, you can't come in here. There's broken glass everywhere, and you could cut yourself.
- This is an old friend of Mommy's I ain't seen in a long time.
- Hi, honey. I'm (bleep)... What's your name?
- Nikki. Such a pretty name for such a pretty girl.
- Nikki, (bleep) asked you a question.
- I'm 4.
[...]