Information that is confidential is meant to be kept secret or private.
She accused them of leaking confidential information about her private life.
她指责他们泄露了有关她的私生活的保密信息。
If you talk to someone in a confidential way, you talk to them quietly because what you are saying is secret or private.
'Look,' he said in a confidential tone, 'I want you to know that me and Joey are cops.'
“喂,”他悄声说,“我想要你知道我和乔伊都是警察。”