Kate Middleton and Prince William helped start the France state visit to the U.K. by welcoming President Emmanuel Macron and his wife, Brigitte Macron, before meeting up with King Charles and Queen Camilla.

According to Nicholl, Prince William "assured Kate she was the one," as he wanted to make sure she realized just how serious he was about their renewed relationship. "William, who had inherited something of his father's fear of commitment, knew he would lose Kate if he could not give her some form of guarantee," Nicholl revealed.