When Daniel was living on the mountain with Rosh, he had one concern only in his life, and that was to defeat the Romans. However, when he moves back to the village, and as he gets to know Joel and Thacia better, he has more contact with those who live normal lives and have normal relationships. His feelings for Thacia are just beginning to awaken. Now that he must care for his sister, his family responsibilities are distracting him from his single objective of overthrowing Roman rule. Just prior to this scene where Leah asks this question, Daniel has gone into a shop to purchase cloth for Leah, and the shop owner assumes he is married. He becomes embarrassed at the idea. Now Leah brings it up again. Daniel doesn't quite know where the anger is coming from--it is like a wound has been opened. He doesn't know whether he is angry at Leah or himself. In fact, this is another facet of his anger towards Rome. Daniel realizes that he cannot marry, first because it would interfere with his only purpose in life, and second because his family and financial situation make him unattractive to the woman he is becoming interested in, namely Thacia. In another world, if his father and mother had not died, his station in life might have been good enough for him to be considered as a match for Thacia. But in his mind, not only have the Romans ruined his past and present, they have also stolen his future. He believes he will never marry. The fact that this question makes him angry indicates that for the first time he is taking an interest in having a normal life and a wife. Of course, his feelings for Thacia, which he does not even recognize yet, have a lot to do with that.