I'm a white American girl and I personally have always been intensely attracted to dark skinned boys and I'm generally not easily turned on by white boys. It all depends on personal preference I guess. I personally would never ever /not/ date someone simply because of their skin, I just find that white boys often seem nice at first but end up being quite annoying and selfish (definitely not all of them, I have plenty of white friends, I'm just saying from personal experience, like half the white guys I know are *******s), whereas South Asian guys are often a little bit more shy and guarded but once you open them up and get to know them, they're a lot more open and honest and sensitive and kind and romantic. My Pakistani boyfriend is fascinated by my blond, thick, wavy hair and pale skin, where as I think I look weird and pink, but everyone has their preferences. If he was white, I would absolutely still date him, I just also find dark skin and any other unfamiliar/unusual physical traits (like weird shaped eyes or thin lips or sharp cheekbones or birthmarks) very attractive and very aesthetically pleasing. Also learning about new cultures and new languages is a lot of fun to me. If the white girl in question is attracted to his personality but is having doubts purely because of his skin color, she's probably not the kind of person you want to be marrying. If there's more to it than that, like if she's worried about the culture gap, then I say if they're in a relationship, they should be able to discuss things openly and point out culture differences and be able to talk it out, as long as neither of them are disrespectful, sexist or racist. I would ask her about it, either by just straight up being like "hey this is totally hypothetical but would you ever marry an Indian guy?" or if you want to be more subtle you can ask her who her celebrity crushes are and see if there's a pattern or "type," or if there's a variety, not just in skin color but in personality, sense of humor, body type, etc. Variety, especially in superficial/physical aspects, is probably better.