The sentence is as follows:

これが兄様がすべてを託した **わけ** なのですか？

From the structure of the sentence this わけ doesn't appear to be a sentence
ending particle, and I'm struggling to interpret it. I find that dictionaries
unfortunately do not actually explain this word in a way that is meaningful
for those who don't already understand how it is used.

To provide some context, the person currently speaking is watching the person
that their 兄様 entrusted something to before their death, where they were also
present at this time. The current time of the statement is as they are
watching the person commit, for lack of a better word, war atrocities in order
to do what they were asked.
CC BY-SA 4.0
2020-05-27T21:16:16.643
77658
2020-05-27T22:49:34.707
39161
question
meaning
What does わけ mean in this sentence
わけ, 訳 is defined as

> conclusion from reasoning, judgement or calculation based on something read
> or heard; reason; cause; meaning; circumstances; situation

When わけ comes at the end of a sentence you can think of it as translating to
"so that means...(the previous words in the sentence), etc". In this case, "So
this is why 兄様 left everything to you?". The speaker is making a conclusion
based on something read or heard.

It has, what I call, continuous form as というわけで、そういうわけで、i.e. "for that/this
reason... blah blah". You'll hear this a lot in Japanese.
CC BY-SA 4.0
2020-05-27T21:36:18.540
77659
2020-05-27T22:04:51.523
2020-05-27T22:04:51.523
22363
22363
77658
answer
"the case":

____わけなのですか = is it the case that ___?
CC BY-SA 4.0
2020-05-27T22:40:27.970
77661
2020-05-27T22:49:34.707
2020-05-27T22:49:34.707
39163
39163
77658
answer