What does でしょうに mean in this situation

Question

I found a related post: https://japanese.stackexchange.com/a/73037/50132.

It seems like the conclusion was that it added a feeling of "当たり前".

According to the other post, （よ）うに can express regret, dissatisfaction, criticism, doubt, emotion, etc. What feeling does it add here?

ねえ お嬢ちゃん何か願い事はあるかしら。（めぐみん）願い事？。遠慮しないで言ってみて。（めぐみん）世界征服！ ごっ ごめんね それは無理だわ。どういうことなのこの子 意外と大物なのかしら。えっと… ほかには何かなあい？（めぐみん）それじゃ 私を巨乳にしてください。ああ… それも無理かなあ。というか お嬢ちゃん 今いくつ？まだ そんな心配する年じゃないでしょうに。（めぐみん）なら…　私を魔王にしてください

Also audio: https://vocaroo.com/1oU3ur1dGKHk.

I wonder if this でしょうに also has a meaning like 当たり前 (something like "obviously that's not an age you worry about having 巨乳, (why would you even ask for it?)"). I assume it doesn't show any irritation about asking in this situation?

Or does this でしょうに maybe have something to do with age? めぐみん in this anime is a little child and the other woman is an adult.

Answer 1

でしょうに is でしょう for inference, followed by the conjunctive particle に meaning "but". This に is the same に used in のに. You can think of でしょうに as a variant of のに but with an added nuance of inference. Its plain (non-polite) version is だろうに.

• 明日は雨が降るのに、出かけるの？ (informal)
  Although (I know) it rains tomorrow, are you going out?
• 明日は雨が降るだろうに、出かけるのか？ (blunt)
  Although it's likely to rain tomorrow, are you going out?
• 明日は雨が降るでしょうに、出かけるのですか？ (polite)
  Although it's likely to rain tomorrow, are you going out?

まだ そんな心配する年じゃないでしょうに。
Although I think you're not old enough to worry about that(, why do you say that)? / But I think you're not old enough to worry about that!

There is no meaning of "obviously/当たり前" in your sentence. In the linked question, such a nuance comes mainly from そりゃあ (=それは). Its literal meaning is close to "As for that" or "When it comes to that", but by extension, it can work like an interjection that implies the feeling of "you know", "why not" or "it's only natural". For example:

• 「明日はサッカーを見るの？」「そりゃ見ますよ！」
  "Are you watching soccer tomorrow?" "Of course, why not!"
• 「なぜ嘘をついたの？」「そりゃあ…」
  "Why did you lie?" "Um...(don't you understand?)"
• Meaning of "そりゃあまぁ"
• かわりもしますよ what is the meaning of this も?