The young lady of the Xu family and the young master of the Zhou family were betrothed before they were even born. Gu Ningning, the Xu family's matriarch, and Xie Duo, the Zhou family's madam, were best friends. The Xu and Zhou families had also been close for generations, and their grandfathers were old friends. The match was originally meant for their generation, but the Xu family had only one son, while the Zhou family had two children. The younger daughter and the Xu family's son weren't interested in each other, and both brought partners home when they graduated from college. The older generation wasn't unreasonable, so all they could say was, "Then let the next generation do it." As it happened, the Xu family's eldest son and the Zhou family's eldest son were born at the same time. Since they were both boys, the families gave up on the idea.
They'd stopped hoping for a match, but then the two families found themselves expecting children at almost the same time. After all those years, both families had nearly abandoned the idea, but as it turned out, this time they were having a boy and a girl. Best of all, the two seemed to take a real liking to each other. They were born just a day apart, with the Zhou family's young master a year older. But after the Xu family's young lady was born, she cried whenever she couldn't see the Zhou family's young master while she slept, and cried whenever she couldn't see him while she drank her milk... In short, she wanted him around every moment of the day. The Zhou family's young master was more reserved with his feelings. When he couldn't see the Xu family's young lady at bedtime, he'd look for her. Before he could talk, he'd wail, and if that didn't work, he'd cry. At feeding time, he insisted that she get her bottle first. These little signs gave both families plenty of hope. After all, before she was even married, Gu Ningning had promised that she would make sure the two families were joined by marriage in the next generation.
It's nice and sweet, but a little lacking.