Im trying to remember the name of a book i read years ago and im going mad!?

it is about a well off young man who lives in a city by the sea. this city is known for its pearl divers and its crossbows make it powerful. he decides against his parents wishes to become a doctor or healer and he then goes out and falls in love with an Indian girl outside of the city. the Indians have a terrible illness and get quarantined. thats all i remember, i know this is incredibly vague but im asking for help here. thanks!