Lover's thorns

A princess hates the prince of the next door kingdom, she puts up with him as their parents are friends. Playing games and having fun, they hate each other with a passion. One day their parents give them an ultimatum they can't refuse. Marry each other and have the whole two kingdoms rule and have the benefits along with it or denounce themselves as an heir and become ordinary citizens. As they don't want to lose either of their titles the princess and prince agree and put up with each other for their parents. Will passion ignite between these two enemies or will it all fail under their terrible ruse to have their titles and benefits.