誰かしら

who could it be?

→ 誰
phrase Rare #24,645
who could it be? Often expresses wondering or uncertainty, and can sound feminine or gentle. The meaning depends on context and intonation.
JA: あの人は誰かしら?
EN: Who could that person be?

誰かしら。

I wonder who it is.

誰かしら?

Who could it be?

— ビッグ・シック ぼくたちの大いなる目ざめ (2017)

彼は誰かしら?

I wonder who he is.

— तुम्बाड (2018)

あの女は誰かしら?

Who is that woman, I wonder?

— 紅夢 (1991)

一体誰かしら?

Who on earth could it be?

あら誰かしらね?

Oh, I wonder who that could be?

— ビッグ・シック ぼくたちの大いなる目ざめ (2017)

誰かしらねあなたごめん

Who are you, I wonder? Sorry.

— アバウト・タイム ~愛おしい時間について~ (2013)

彼女は誰かしら。

I wonder who she is.