Im new. I just saw the movie and I understood it completely different as you guys/girls
Sorry for my english but it is not my first language
1. IMO, the ending was brilliant because you understand more why she couldn't reveal her source:
First, cause she had to maintain her professional integrity
Second, cause after the death of the agent, she couldn't be responsable for the little girl feeling guilty all her life of killing her mother
Third, cause the source did not even know that she was doing something forbidden when she gave the information
2. When the judge let her free and they arrested her, she was given two options: To declare herlself innocent, go to trial and spend 5 years in prison (cause with all the proof they would declare her guilty) or to declare herself guilty (whithout going to trial) and spend two years in prison. It wasnt about the source anymore. So she declare herself guilty as charge on the condition that she sees her son before going to prison.
I really loved this movie. Cause at first I loved her for doing what was right and protecting her source but then when all went crazy and she spent nearly a year in jail, I thought she was nuts. It had to be another reason why she wouldn't tell her source and I knew it at the end of the movie
Hope you guys understand my opinion.