How is Wang's marriage more like business transaction than a romance?

The time comes for him to request his bride at the Great House of Hwang. He is terribly anxious, however, and decides to eat something before going forth. When he arrives at the gate of the Great House he is greeted by the gateman, a very unpleasant man that requires Wang Lung to give him a piece of silver before he is shown into the house.

Wang Lung is taken to see the Old Mistress, a very intimidating figure. The Mistress speaks of O-lan, his soon to be wife. She is described as plain but hard-working, presumably also a virgin, though in Great Houses the masters often had their way with the slaves. Regardless, O-lan's lack of beauty has prevented the masters from taking any interest in her. She is also described as slow. The Old Mistress states her desire to see their firstborn and then swiftly hands O-lan over to Wang Lung. In a moment she passes from one master to another, no questions asked.