How can one deal with a young man who persists in pursuing, while desiring to focus on pleasing Allah?

If the pursuit is for seduction, then turn to Allah to protect you from him, remind him of Allah, and threaten him with informing your guardian or the authorities. Be careful not to be alone with him.

However, if the pursuit is for marriage and you wish to marry him, and he is capable of being just, then propose marriage to him on the condition of his repentance and righteousness.