Admittance rhymes with:
remittance, pittance, remittance, acceptance, acquaintance, assistance, capacitance, coexistence, consistence, constance, distance, existence, importance, impotence, inadvertence, incompetence, inductance, inheritance, insistence, instance, omnipotence, outdistance, persistence, pittance, quaintance, reluctance, remittance, repentance, resistance, resistence, self-subsistence, sentence, subsistence, substance
Admittance sounds like:
addendums, admitting, admonitions, attendance, attending, attentions, automating