Pianist's rhymes with:
pianists, pianists, pianists, abolitionists, antagonists, arsonists, chauvinists, columnists, communist's, communists, conservationists, ernest's, ernests, exhibitionists, feminists, humanists, illusionist's, illusionists, jansenists, modernists, obstructionists, perfectionists, pianists, platonists, protagonists, violinists
Pianist's sounds like:
pianists, pinochet's, pneumocystis, poinsettias