plea bargaining in the U.S also is a promise that they will recommend that you get a particular deal, but the judge in sentencing can decide not to take that deal.
Yes maybe my wording was clumsy but that is what I was attempting to say. The important thing is the prosecutor is not allowed to lie to you as part of the plea bargain. If they promise to do something like give a specific recommendation to the judge they must do it or risk the verdict being overturned.