u/Bluepurple103

Read years ago - its about a girl who is separated from her twin brother, as twins are unusual and could be powerful with joint magic.

She then joins a new high-school and her twin brother is there. She meets someone and falls in love - he is the evil l kings son. Her brother and their family are part of the rebellion.

I remember when the kings son proposes to her, turns out it is a distraction so the king can capture the rebellion. She realises and goes to fight in support of the rebellion.