Sincere rhymes with:
insincere, insincere, financier, financiere, insincere, bassir, cyr, desir, financier, financiere, insincere, sear, sere
Sincere sounds like:
saenger, samcor, samsara, sanger, sankara, sanker, schenker, schmeiser, schmoker, schmucker, schnauzer, schoemaker, schoenecker, schomaker, schoonmaker, schuhmacher, schumacher, schumacker, schumaker, schwenker, schwinger, seckinger, seneker, senger, sensor, sensory, shangri, shankar, shanker, shenker, shewmaker, shoemaker, shomaker, shoumaker, shumaker, sickinger, sinagra, singer, sinker, smasher, smoker, smucker, smyser, snagger, snazzier, sneaker, snicker, snooker, songer, suncor, sunseri, swanger, swinger, swonger, synchro, syncor