Can You Be My Sweetheart?

I was obsessed with martial arts, and my master was obsessed with picking up children. Unfortunately, the brothers and sisters whom my master picked up never came back after they went down the mountain. In the end, I was the only one beside my master. However, I was driven down the mountain by my master. He said that only by finding my sweetheart and then killing my sweetheart can I master the highest martial arts of our sect. It's no problem to go down the mountain, but who is your sweetheart?