Forgot name on this manga

Tried to search different part of story to see if I could find it but got no luck.

It’s about a girl that reincarnated and had lots of magic power, she goes into kinda saintess school(?) and then meet prince there. Both prince and ml was lover in previous lifetime and both remember. But due to misunderstanding and scheming from enemies they both couldn’t be together. In this timeline girl found her old ring that prince gave to her in previous life deep under ground and learned that prince did not forget her and still love her after all.

I want to read this manga so badly but can’t for life find it again :(