I need help on the private caveat issue.

Last month, I asked my tenant to move out since I plan to sell the house.
The problem is that, the tenant had renovated my house without my consent (he initially planned to buy my house).
Now he threatens me to lodge a private caveat on the property to stop any selling procedures until I pay the renovation cost.
I don't have any tenancy agreement with him, however, I did text him before the renovation that I won't bear the renovation cost (he agreed).

In case he applies for private caveat, can I remove it by simply filling the 19H form?
Is this thing is eligible for private caveat claim?
I need to sell the house fast, if possible, I hope I'm not going to settle this matter in court.