Capítulo 714: Final Battle - Part 4

Yes, Robert betrayed this woman because Rosalie rejected his confession by saying she had someone she loved. Jealousy and ambition took over him, and he plotted the rebellion. The rebellion was just a trick to force Rosalie to accept him, but until the last moment, Rosalie still rejected him.

Even when she was poisoned with Mana Corroder, the poison that ate her mana, causing her not to be able to execute any skill, she still rejected her. He threatened her that he would sell her to whore house for the nobles after having fun with her. Even after all of that, the woman chose to kill herself instead of accepting him. The person who had been loyal to her, helping her to establish the strongest kingdom in the Ortis Continent.