In Much Ado About Nothing, there is at one point the following sentence (Act 2, Scene 1, spoken by Benedick):
I am not so reputed; it is the base, though bitter, disposition of Beatrice that puts the world into her person and so gives me out.
Here the phrase "puts the world into her person and so gives me out" means "claims to speak for everyone else, representing her own opinion as the world's, and so portrays me according to that opinion", according to my annotated edition.
I quite like this turn of phrase, but is there an idiomatic expression that captures this meaning eloquently in modern English?
Edit: here's an example with David Tennant: https://youtu.be/UNIQm7vEa2o?t=30s
Edit 2: I really feel I should say that I think the (rest of the) play does seem to make it clear that it's not a habitual fault of Beatrice, but something one-off. So the phrase is describing a single instance of such behaviour (by Beatrice), not an indelible permanent personality fault, as some answers seem to assume. Maybe it's ambiguous in my question, but I mean to ask about the phrase as it was used in the play.
Bounty note: in the absence of consensus (most answers had 0 votes, the highest only 2), and given that the suggestions are quite far from the original phrase's meaning, I'll award the bounty to the answer that says it can't be done.