"I am affected, not because you have deceived me, but because I can no longer believe in you."
This quote simply is stating that a person does not have to directly tell a lie in order fro you to not believe i them. The key is the word "in". he says i can no longer believe IN you. rather than i can no longer believe you. He is saying that a person may no have to deceive you in order for you to lose faith in them s a human being. They ma have displayed a sense of poo moral judgement or you may not agree with their practices or beliefs so although they have no lied or been false, you still do not believe in them as a human.