My soon-to-be sister-in-law is Chinese. My future wife is her older sister, so she doesn't feel comfortable calling me by my given name. In Chinese she would call be 姐夫, for which the nearest English translation seems to be "brother in law" or "husband of older sister", which is a bit of a mouthful to say the least. Even just "brother in law" is a bit much.
Is there are more appropriate term in English that I can suggest? I don't want her to feel uncomfortable.