Check veracrypt. It allows you to create a “partition” that looks as a file and you can have that option of the fake password.

Its been several time since I’ve used it, so I don’t remember the exact details. If you need help I could make a tutorial

If you want to be really secure you can encrypt it. By hand it would be difficult, but with enough time I think you could get used to it.

On digital you may have an encrypted drive with a fake password. That way using your fake password it shows some decoy files that you don’t care about. And using the real password it shows your journal.