(Not to be confused with the Secret Notes).
Jane's Private Classes are secret classes between Jane, the Protagonist and Molly.
The classes are available on all routes.
On the Heroic route, this route is unlocked by completing Sarah's Mind. In it, the Protagonist uses Suppress on Molly. The Protagonist starts with this spell by default.
If you're on the Heroic Route and told Jane that you're worried about abusing your powers, Molly joins your party.
In the second class, you need access to the Charm spell. To access it, you need 150 Debilitating proficiency.
If you're on the Tempted Hero route, Molly joins your party after this class due to finding out that Drape have attacked two of the Protagonist's friends (Val and Sarah).
In the third class, you need access to the Flirt spell. This requires 110 Support proficiency.
In the fourth class, you need access to the Transform spell. This requires 200 Physical proficiency.
If you transform into Jane during this class and then use Confuse on her, you enslave both Jane and Molly at the same time. This allows you to add Molly into your party from the bedroom as well as changing her personalities.
If you transform into Molly, you need to get your own nature reinforced in order to change back into the Protagonist. Should you get Molly's personality reinforced rather than your own, the Protagonist will forget how to use the Transform spell, leading to an ending.
There is an alternate version with other dialogue and other ending if Molly is in Succubus form.
If you don't want to go on the Heroic route, you can unlock these classes by enslaving any three people. The earliest you can do so is after reaching floor three, by enslaving Val at first, then Sarah in the hallway, then finally Julia once you've attended the first Secret Notes class.