Daisy did not take the bait, which were Gatsby's parties, so he uses Nick to get Daisy. Also, They met each other in college, Gatsby went off to war, and Daisy did not hear from him for 5 years.
It means that all the things that have the impression that the place was ugly and dull disappeared in the light of twilight. In the twilight it looked powerful and beautiful.
Belinda called the office because she was running late.