Wel - ( Not's opposite - expresses affirmation - adds Verbal positive emphasis - like Do & Does - Well, yes I do! - Well, so does he! ) • From Middle Dutch - Wel • from Old Dutch - Wela, Wala • from Proto-Germanic - Wela • from Proto-Indo-European Welh₁- • Compare German - Wohl, English - Well • Icelandic - Vel • Swedish - Väl • Danish & ** Norwegian - Vel
English doesn't have this construct. Instead, you repeat the verb that was denied in the first part of the contradiction (in the appropriate form for the second part). Sometimes, using an auxiliary verb works better.
He isn't very bright, but you are.
They have no money, but she has.
I wasn't allowed to kiss her, but he was.