Yes, we will not

Figure of speech. To Stephen's arch parliamentary suggestion that the company adjourn for some refreshment, Lenehan responds with an arch proposal to renounce alcohol: "We will sternly refuse to partake of strong waters, will we not?" Then he negates his negation: "Yes, we will not. By no manner of means." In terms of rhetorical theory he has performed a kind of litotes, a type of understatement that affirms something by negating its opposite.

John Hunt 2023

Sandwich being regarded as very good. Source:

Victoria showing that she is not amused. Source: