Peik Lin is Rachel's BFF, and turns out to be a critical friend to Rachel during her stay in Singapore. In many ways Peik Lin becomes the translator for Rachel to help her understand what is going on in the world of the massively wealthy.
Her family would be considered "new money" in Singapore, as her family assembled their wealth only in her father's lifetime. He is the "Chinese-educated son of a Hainanese immigrant" which put him at an immediate disadvantage in Singapore. What her family lacks in elite social status (but let's be clear, they are wealth and elite), they make up for in hard work, kindness, and super gold decorations.
Peik Lin works for her father, but also works hard to make sure Rachel is accepted by Nick's family. She is stunned to uncover the crowd that Rachel has stumbled upon: Colin Khoo, Araminta Lee, and whatever old person lives in the huge house at Tyersall Park. True to being "generous to a fault," Peik Lin buys outfit after outfit for Rachel to make sure she gives the right impression (1.16.20).
In the end, Peik Lin and her family are the ones in Singapore who unreservedly accept Rachel, even giving her refuge after everything falls apart with Nick. They feed her, comfort her, and make sure she knows that she deserves the best from anyone. Peik Lin and her family illustrate that not all wealthy families are cutthroat and awful: some of them are just kind families with lots of money…and lots of ridiculous gold décor.