I couldn't believe what Prince Francis did after his crowning ceremony ended. He suddenly took Olivia as his crown princess in front of everyone. Even the emperor was so surprised and because of the rumor he couldn't trust Olivia. But Prince Francis convinced him and even more surprisingly he was willing to be punished together with Olivia if they found her betraying them.
In conclusion, from my point of view, Olivia was Prince Francis' greatest weakness. He was even willing to do everything for that girl, even if it would cost his life. Everything would depend on Olivia, on how she planned everything for the future.