Peony

She's a princess that ran away from her kingdom to defy her arranged marriage. 

To survive outside her kingdom home she took training as an assassin with the neighbored kingdom.
There she found her love, hope, family, and peace.  

Unfortunately, her new kingdom was ambushed with a surprise attacked by her father's order. They killed everyone leaving her isolated, abandoned and alone.
 With this, she made a promise to seek revenge.