I recently came across the phrase
じゃないんじゃない in this sentence:
Clerk: でも うちで売ってるアイスじゃないんじゃないかしら
For context, some kids are claiming they have a winning popsicle stick but the clerk can't seem to recognize it.
Here, I believe the clerk is saying
But I don't think we sell this kind of ice cream here.
じゃないんじゃない is throwing me off because it looks like it's negating the sentence while also asking for confirmation, as if the clerk doesn't believe her own words or something.
じゃないんじゃない be translated here?