Sweetener rhymes with:
quintanar, aachener, airconditioner, almoner, commissioner, commoner, conditioner, confectioner, coroner, examiner, executioner, falconer, fastener, faulconer, foreigner, freshener, gardener, gissendanner, hardener, heavener, kamenar, kitchener, laminer, listener, londoner, mariner, masoner, oftener, opener, parishioner, pensioner, petitioner, practitioner, prisoner, probationer, questioner, quintanar, reasoner, rosener, schuldener, softener, stationer, stiffener, thickener, tichenor, usinor, vacationer, vanwagoner, wagener, waggener, waggoner, wagoner, warriner
Sweetener sounds like:
saidiner, schattner, seidner, shatner, sidener, sitmar, sittner, skidmore, sotomayor, stahmer, stamer, stammer, stamour, staniar, stanmore, stationary, stationer, stationery, stayner, steamer, steamier, steimer, steiner, steinhauer, steinmeyer, steinroe, stemmer, stenner, stettner, stinar, stiner, stoner, stoneware, stoudemire, stoudenmire, stunner, stutner, st_marie, st_mary, sutner, suttmeier, sydnor