He doesn’t have to go as far as pardoning her. It can be a plea deal type of thing. That will require some level of cooperation from the courts, which is probably what they are negotiating right now. She has no leverage to make threats (“pardon me or I’ll expose you”) because her life is already forfeit, as Epstein’s death shows. So she’ll go along with even a weak deal like a long prison stance but under more comfortable conditions, with perhaps some assurances she won’t suddenly commit suicide.