Essentially Pelosi is offering him his show trial "exoneration", in exchange for putting Bolton's testimony on the record.
With the caveat that even if he were to concede to every demand, she could still delay things and try to extract even more political advantage anyway.
Unless, as has been suggested, there is no deal, and Pelosi's plan is to extract as much political advantage from the process as possible, ahead of the election, without going to trial.
I think if that's the plan, it's likely to backfire.