adjective & verb form of "fidelity" [closed]

Can anyone tell me the etymological root of the word "fidelity" ? I've found here the adjective form of it to be "fidelitous" (faithful). I don't know whether it's correct. And what is the verb of it (i.e to trust) ?

Solution 1:

Based on (Merriam-Webster Online's definition), it comes from Latin (by way of French and Middle English): fides meaning faith and fidere meaning to trust.

Fidelitous is the adjective, although it's not used all that commonly. There's not a verb form that I've seen or can find, and the verb form wouldn't mean "to trust," but "to be faithful."

Solution 2:

An English verb phrase along the same lines is to keep faith. There are not many definitions online; Wiktionary says

(transitive)to continue to have confidence in someone or something, and to support them or it