Smarten rhymes with:
marten, martin, marton, mcmartin, barten, barton, carton, darton, garten, garton, harten, harton, hearten, marten, martin, marton, mccartan, mccarten, mccartin, mcmartin, parten, parton, spartan, tartan
Smarten sounds like:
samaritan, sammartino, sanmartin, smartmoney, somerton, summertime