Why does no one seem worried about how Robin will react when and if he finds out Regina was responsible for the supposed death of Marion?

あなた mean he really forgave Regina that quickly?

Possibly, but what she did was in the past and they're currently in the present/future, and like Marion 発言しました he did 移動する on.

Wow talk about honor! I 愛 Regina but not gonna lie. I wouldn't be so forgiving that quickly if the person I was in 愛 with was responsible for the supposed death of my 前 love.

That would be true.