How to get my husband on my side (novel)

In the original lines of the novel, I was a villainess-used as a political tool by my father and older brother-who ended up dying at the hands of my future husband. To save his kingdom, my father desperately begged my fifth groom to take my hand in marriage. The problem is that the man I'm supposed to marry, the legendary knight of the North, is the same man who will end up murdering me and my entire family. I have to find a way to survive. Within the novel itself, there are many daunting challenges ahead of me: I have to find a way to save my husband's little sister, win over my cold-hearted husband, and gain the support of the people of the North, all of whom currently despise me. "I'm in love with you!" So please, don't kill me!