I am a boy, and my peace elite apprentice is a girl. My apprentice told me in the game that we are husband's wife for the time being. What does my apprentice mean?

Maybe it was a joke at first. Maybe girls like you, that's all. If you two get along well, if you are both single, you still have a chance to catch up with her. She is willing to call you husband and wife temporarily, which shows that girls don't dislike you. If you like her, you can say I miss you and be my wife in life.