Three In a Family (1990)

Cheng Zi-dong works as a sales manager for household appliances. He and his girlfriend, Lu Jiayi , are preparing to get married and buy an affordable apartment. Cheng discovers a cheap apartment and plans to buy it with Lu, but they don't have enough money for the down payment. Lu borrows money from her sister, who lives with Cheng, causing tension. Later, Lu's sister joins Cheng's company, leading to more conflicts.