IPA: /ˌkɒn.fɪˈden.ʃəl/
KK: /kɒnˈfɪdɛnʃəl/
Relating to information that is meant to be kept secret or private, often because revealing it could cause harm or breach trust.
The lawyer assured her that all discussions would remain confidential.
Confidential → It is formed from "con-" (meaning together) and "fidelis" (meaning faithful or loyal). The word "confidential" refers to information that is meant to be kept faithful or loyal to a specific person or group, thus not shared publicly.
Think of information that is kept 'faithful' ('fidelis') to a person or group, and 'together' ('con-') means it should stay private.