What does 그러신데 or 저러신데 mean?

See a translation

신데 = 시 + ㄴ + 데
시- : honorific particle
-ㄴ- : determiner suffix attached to a verb stem without a consonant, or with a consonant ‘ㄹ’ or after the end ‘-으시-’ for...
1. A suffix used to indicate that an event or action took place in the past or in the past rather than the reference point assumed by the speaker.
2. A suffix indicating that an event or action has been completed and that the state is maintained.
-데 : A ending used to indicate that a fact that has been learned through direct experience at some point in the past is transferred to the present speaking scene as it is.
ㅡㅡㅡ
fiou.....so....
Scrooge suddenly says he will give all the money to the needy.
the we can say '왜 저러신데?' 'why does he do that?'
there are not particular english words corresponding to 신데...
only to sense it's nuance by learning...