I had to translate this for a novel once, and my research convinced me that there isn't an exact equivalent in English. I can't now lay hands on the Ms. I translated, but I wound up doing something like "a sense of style you don't come across every day." Obviously, adapt to your needs.

A couple of notes: (1) I'd avoid "class" because it risks getting mixed up with "social class"'; this saying is not about social or economic class. (2) Similarly, don't get mixed up w/blood/water -- I've seen this translated as "breeding will tell," which is a snotty (and inaccurate) way to put what's actually a pretty noble sentiment.

I'd say. I don't think there's a direct equivalent..