Not an April fool joke

[Silverobama]

Someone sent me a message and said she wanted to ask me out on a date. I replied to her "You sure this is not an April Fool Joke?"

Is my sentence natural?

 

[Glizdka]

Not a teacher (added by a moderator.)

I wouldn't ask someone whether they are sure if they're not joking. They already knew that before asking you out on a date. I'd replace sure with really and say something like this:

"Is this really not an April Fool's prank?"

This way, you're questioning their genuineness, not certainty, which I think makes more sense.

 

[5jj]

"You sure this is not an April Fool Joke?"

Is my sentence natural?

It's OK.