Matrimonial rhymes with:
ceremonial, ceremonial, testimonial, ceremonial, testimonial, ceremonial, colonial, testimonial, bicentennial, biennial, centennial, ceremonial, colonial, company'll, decennial, intracranial, lineal, matrilineal, menial, millennial, patrilineal, perennial, quadrennial, testimonial, triennial
Matrimonial sounds like:
maternal, matronly, metromail, mother-in-law