Although it's not the case that Maruo was asked by anyone, he did the classroom cleaning by himself.
...わけではない = It's not the case that ...
だれも = anyone
I'm confused as to how these merge together into the above sentence (assuming my translation is correct).
Naively (and no doubt wrongly) I would have tried だれにも頼まれたわけではないのに. Is there a way to understand what is going on here?
Also, If I simply wanted to say "I wasn't asked by anyone" (without all the わけ stuff) how would I do that? Again, naivley I'd try だれにも頼まれなかった、but something tells me I'm wrong.