Here's what rhymes with cretainly.
                        
                        
                    
                                mainly  plainly  vainly  sanely  inanely  insanely  ungainly  humanely  profanely  mundanely  inhumanely  Words that almost rhyme with cretainly
tamely  namely  lamely  gamely  daily  dainty  basely  bailey  paisley  palely  baby  lately  safely  faintly  rainy  stately  vaguely  bravely  gaily  saintly  seine  tasty  daisy  gayly  innately  pasty  shapely  mangy  regale  sagely  sedately  stably  brainy  chastely  rangy  zany  dazedly  opaquely  staidly  saintlier  pacey  greatly  lady  safety  maybe  navy  strangely  gravely  hasty  lazy  facie  hazy  shady  shaky  wavy  weighty  pastry  quaintly  racy  grainy  lacy  precis  wadi  platy  cagey  stagey  straightly  crybaby  matey  spacey  stagy  irately  cagy  frailly  majorly  rubati  crazy  frailty  gravy  clayey  flaky  savoury  chaplaincy  ornately  snaky  chickadee  milady  strati  averagely  unshapely  archaically  concavely  unsafely  unstably  quaky  miscellany  scrapie  ukulele  desolately  chocolaty  staccati  unsavoury  intestacy  overhasty  cockamamie  charlady  pizzicati  profligately  obbligati  hippopotami  recognisably  shamefacedly  saleslady  barefacedly  magistracy  disconsolately