Under The Code Name K213 1985 on netflix

Spy film set in southern Vietnam after liberation. Thach Thao befriends Thanh, the son a police official, so she can easily pass police posts. She persuades her former boyfriend’s sister to emigrate illegally. The police begin to suspect her as a spy. Using the code-name K213 she has returned from abroad to contact counterrevolutionary groups masquerading as religious organizations. After a battle, the police arrest all the plotters.