Sweeteners rhymes with:
commissioner's, commissioners, commoners, conditioners, confectioners, coroner's, coroners, examiner's, executioner's, executioners, falconers, fasteners, foreigners, foreigners', fresheners, gardener's, gardeners, hardeners, listeners, londoners, mariners, openers, parishioners, pensioners, petitioners, practitioners, prisoner's, prisoners, prisoners', probationers, questioners, reasoner's, schuldener's, stationers, vacationers, vacationers'
Sweeteners sounds like:
southmark, southmark's, stationers, steamers, steiner's, stonerock