I'm an Opportunistic Princess in Charge of Solving Things

Story:

Princess Octavia was a high school student until she was reborn in the world of her beloved novel, The Noble King. In this novel, she saw her brother with another man in a very close relationship. If so, will there be problems with future heirs? They will never force me to enter into a political marriage to give them a child, right ?! I don't want to be a character that is being used! If this is true, then I will definitely find my partner and love to be happy.