The Necessary Wife (2001)

Tawan is an orphan who lives a Cinderella life with her aunt and cousin Yardfah. She was treated like a servant and did whatever she was told to do. Her cousin’s dad and Tomorn’s dad arranged a marriage between her cousin Yardfah and Tomorn when they were kids. Years pass by, her aunt’s status changed but Tomorn’s dad wants to keep his promise to give his son away. Tomorn hates the idea but agrees to meet Yardfah before making his decision. He ends up falling in love at first sight but it was with Tawan instead. When Tawan’s aunt found out, she made Tawan pretend to be her daughter because she wanted his money.