If you tell something to someone in confidence, you do not want them to tell anyone else.

Any personal data you provide to us will be held in confidence.

Whatever you tell us will be kept in strict confidence.

I told you that in confidence!

Some of the students came forward, in confidence, and told the head teacher what they had heard.

I don't want to reveal any information that was given to me in confidence.

See also: confidence (SECRET)