"Sage" means "scholar" in ancient times, which means that people are very profound and great. And he has profound attainments in moral, intellectual and physical aspects, and is in a leading position in a certain field. For example, "Mahatma" Gandhi is the father of India; Li Bai is called "Poet Saint"; Sun Zhongjing is called a "medical sage" and so on.
Besides, Xuan means imposing and distinguished. In ancient times, there was a man named Xuanyuan who was very imposing, so the word "Xuan" has always been highly respected and loved.
And the combination of the two, which contains the meaning, is self-evident.