Hire a Secret Guard as a Son-In-Law

I, the daughter of the richest businessman in the capital, have only one condition for recruiting a son-in-law: he can beat me. In the past three years, I have played countless games, until a masked swordsman came and knocked my sword away with ten moves. On the night of the wedding, he took off his mask to reveal the face of the enemy I had been hunting for three years. "Madam," he smiled and took out a stack of paper, "this is the letter of challenge you wrote to me back then, 98 letters in total." "Now it's your turn to make good on your 'at my disposal' promise."