が一人もいない

not have a single…

→ が

phrase Rare #34,384

not have a single… Emphasizes that there are none at all; 一人もいない literally means “not even one person is there.”

JA: 私のクラスには日本語を話せる人が一人もいない。

EN: There isn’t a single person in my class who can speak Japanese.

彼には友達が一人もいない。

He doesn't have a single friend.

トムには友達が一人もいない。

Tom doesn't have any friends.

私にはガールフレンドが一人もいない。

I don't have a single girlfriend.

彼には自分を継承してくれる子供が一人もいない。

He doesn't have a single child to carry on his legacy.