The word "now" is used here to mark a break in the main story line. Here Luke tells background information about the people in Berea and how they were willing to listen to Paul and examine what he said. (See: [[rc://en/ta/man/jit/writing-background]])
These "well-born" people were willing to think more objectively about new ideas than other people. Alternate translation: "more open minded" or "more willing to listen"