When Henry meets his soon-to-be daughter-in-law, he's surprised to see that she isn't Chinese. This passes quickly, though, and he immediately takes to her warm and friendly nature. For her part, Samantha tries her hardest to win Henry over, even planning and cooking a traditional Chinese meal for him:
Samantha had gone inside to pick up a few things—she insisted on making dinner for all of them, a Chinese dinner. Why, or what she might be trying to prove, Henry couldn't ascertain, and honestly, he didn't care. She could have made huevos rancheros or coq au vin and he'd have been fine with it. (29.1)
Samantha immediately accepts Henry as a member of her own family and treats him with kindness and compassion, which helps him see how good she is for Marty. It's obvious that Samantha loves Marty and will do whatever it takes to make him happy—and that's what's really important in a relationship, not race.