I don't know anything.
I don't know anything about it whatsoever.
I don't know anything.
I don't know anything about it.
I fail to see.
(何も知らない).
I don't know anything at all.
I don't know anything about ~ .
I wish I can help you, but I don't know
Don't understand anything
I don't know anything about that.
I know nothing whatever about it.
知らないわ。