Here's what rhymes with believably.
unbelievably conceivably irretrievably inconceivably Words that almost rhyme with believably
appreciably peaceably feasibly inappreciably unrelievedly indefeasibly legally agreeably grievously unevenly regally illegally greedily regency zealously aridity dreamily realty sleepily drearily cheekily creakily creepily anemically creamily recently deity speedily ceaselessly fealty needlessly uneasily unequally gleefully leniency serenely unspeakably disagreeably genially heedlessly leniently naivety piquancy seamlessly deceitfully egregiously irredeemably obscenely peony breezily dubiety phonemically covetously greasily heedfully needfully piquantly sleeplessly sneakily wheezily sleazily frequency frequently secrecy decency peacefully supremely decently ideality facetiously speciously speechlessly queasily coequally squeakily obesity ingeniously unfrequently coherently benignity congenially heterogeneously conveniently infrequently crystallinity indecency infrequency indecently homogeneity spontaneity centripetally heterogeneity historicity simultaneity inconveniently contemporaneity