Japanese phrase
本当に___が原因ですか？ hon tō ni ___ ga gen in de su ka
Meaning
Is ___ really the cause?
When to use it
Asks whether something is truly the cause of a problem. It shows doubt and seeks confirmation in a direct but polite way.
Example dialogue
本当に寝不足が原因ですか？ hon tō ni ne bu soku ga gen in de su ka
Is lack of sleep really the cause?
そうかもしれません。 sō ka mo shi re ma se n
It might be.