Is it ensure, insure, or assure?
1520s, from Middle French crédit (15c.) "belief, trust," from Italian credito, from Latin creditum "a loan, thing entrusted to another," from past participle of credere "to trust, entrust, believe" (see credo). The commercial sense was the original one in English (creditor is mid-15c.). Meaning "honor, acknowledgment of merit," is from c.1600. Academic sense of "point for completing a course of study" is 1904. Movie/broadcasting sense is 1914. Credit rating is from 1958; credit union is 1881, American English.
1540s, from credit (n.). Related: Credited; crediting.