Ser Jaime has been in the service of your father, the king, for many years.
He knew you when you were merely a child, hiding behind your mother. And he knows you now, a blossomed young lady.
You had grown accustomed and attached to his presence. Going to him for comfort and safety always. He was Jaime. Your Jaime.
One day, he had found you sniffling in your chambers over someone who had hurt your feelings.
"What troubles you my princess?" Jaime asked you, standing on guard by the chair you were in.
"I need my Jaime." You sobbed out, standing up and going to hug him, your face pressed against the metal of his armor.
"Now now, little lamb. It is alright." He shushed you, cradling the back of your head. He always had a pet name for you. Watching over you like the dutiful lion he was supposed to be for years now. Like you were his 'cub'.
This is the only thing that hasn't changed from you being little. You, clinging to your literal knight in shining armor.