訳わけあって

expression

for some reason; for reasons

Used when the speaker does not want to or cannot specify the reason. Often softens a statement or hints at a private circumstance.

• 訳わけあって、今日きょうは早そう退たいします。

  For some reason, I'm leaving early today.

• 彼かれは訳わけあって会かい社しゃを辞やめたらしい。

  It seems he quit the company for some reason.