Student or Learner
A person who keeps your secrets is called confidant. What adjective do you use to express this characteristic?
Perhaps trustworthy? Or discreet?
I'm not a teacher, but I write for a living. Please don't ask me about 2nd conditionals, but I'm a safe bet for what reads well in (American) English.
As 'the word' was confidant that would have been a better thread title.
But confidential means secret.
You can have a confidential secretary, for instance, who is trusted with things other people are not.
I'm honestly not sure- it's used in BrE, but the AHD gives it: confidential - definition of confidential by the Free Online Dictionary, Thesaurus and Encyclopedia..
To me, "hav[ing] a confidential secretary" sounds like you have a secret secretary that know one knows about