Here's what rhymes with decertify.
high thy vi hi shy sigh fi hy thigh vie certify psi hai cy fy sy thei phi by my why die lie y buy fly sky guy satisfy tie modify bi bye chi defy dye nigh pi pie spy thai dei fry ly quae rye sly ty wir awry lye mai muy nai ratify wry kai lai luy mei tai wai edify sty bonsai deify ossify stye turfy versify beatify slier apply dry try cry deny justify testify verify butterfly gratify notify ply underlie alibi amplify diversify nullify pacify pry tri trie belie pri terrify typify untie codify mollify personify ramify acidify aquae spry stratify stultify amebae horrify dissatisfy lanai mummify shanghai vitrify speechify banzais dandify yuppify supply thereby occupy rely hereby qualify specify alkali classify signify simplify purify fortify magnify rectify samurai unify decry falsify lullaby pupae solidify amoebae descry dignify overlie vilify demystify firefly mystify ultrahigh vivify blowfly calcify petrify stupefy overfly scarify scurfy barfly hyperbolae prettify overbuy identify reply imply nearby whereby clarify comply multiply glorify goodbye quantify alveoli standby beautify disqualify termini crucify liquefy mortify objectify oversupply resupply detoxify retry triply emulsify reunify liquify declassify drachmai refortify ripply syllabify stimuli nuclei exemplify intensify indemnify dragonfly electrify preoccupy misapply reclassify revivify gentrify solemnify oversimplify misidentify transmogrify cumuli