Hahaha, this one felt awful. I have to admit, this is definitely the first time I've seen a villainess rejection template go in this particular direction, but there's definitely a reason why nobody does this, lmao.
I've read some enjoyable stories where the prince fakes the annulment or pretends to flirt with another girl as a test, but in 100% of those, it backfires on him terribly in some way or another. Because all of those writers knew that this is a tremendously shitty thing to do, and having him turn around and say "actually, I do love you, I just wanted to humiliate you publicly because I felt insecure about our relationship" isn't romantic or charming in the slightest.
Even stories where the prince ultimately redeems himself and wins the protagonist back have him go through some well-deserved strife first, because it's just not satisfying unless he suffers at least a little bit for his mistake! As it is, it's just, jeez, girl, grow a spine. Have some self-respect.