Middle English word redden comes from Middle English reden (To counsel, advise. To read. To study.), Proto-Indo-European *kert-

Detailed word origin of redden

Dictionary entry	Language	Definition
reden	Middle English (enm)	To counsel, advise. To read. To study.
*kert-	Proto-Indo-European (ine-pro)
*hradjaną	Proto-Germanic (gem-pro)	To loosen; set free; deliver; rescue; save.
hreddan	Old English (ang)	To deliver, free from; take away. To recover. To save, rescue.
redden	Middle English (enm)

Words with the same origin as redden