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{う}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
.
However, the 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.
How should じゃないんじゃない
be translated here?