The effects of betrayal are explored throughout the film.
Leon betrays Sonja
Sonja says that the betrayal exists not within the act but the lying. "It isn't that he's slept with another woman, it's that he's lied to me about it that's the betrayal."
Patrick’s lover is betraying his family.
Jane betrays her friendship with Paula.
John confides in Leon that he has had an affair, and as a result "something (within the marriage) gets broken permanently - trust, I suppose". Later, John admits to Leon the awful truth, that he was home the night Valerie rang, desperately seeking his help. "I didn't pick up the phone - I thought she would come home."
Sonja's tells Valerie her criteria for a successful marriage - "passionate, challenging and honest".
The marriage of Paula and Nic is based on trust. Nic tells Paula when he thinks Jane is trying to seduce him. He refuses to speak to the police until Paula arrives to reassure her that he is innocent. When Jane asks how Paula knows Nic is innocent she replies “because he told me.”
Leon confronts the state of his own marriage after witnessing Nic and Paula in the interview room.
Valerie’s lack of trust leads to her paranoia and ultimate demise