In English you can use a double negative to give a wishy washy response.
Question: "Are you happy?"
Response: “I’m not not happy.”
I googled “japanese double negative”, and found stuff about なくはない here. The article says:
Double negative means that the negative form is used twice in a single sentence. However, that’s not the same nuance as positive sentences. […], double negatives are closer to normal negative sentences.
Based on this article, saying「嬉しくなくはない」would be closer to saying 「嬉しくない」 than 「嬉しい」. To the people who have heard this in context, do you agree that this construct is more similar to the negative than the positive?
Also, I’m wondering if this has the same nuance between Japanese and English. Do you guys think the English “I’m not not happy” similarly is closer to “I’m not happy”? Or would you say it’s closer to “I am happy”. Or is it more neutral? I can’t pin down exactly what the nuance is even in English, so I’d appreciate other opinions.
Finally if there is another (or a better) way to say something like “I’m not not happy”, please let me know.