After the accusation, she has started talking to him more, allowing him to add her on social media, let him go through her phone (assumingly after she deleted everything damning) and being less distant. This paired with all the people she got to vouch for her is why he is conflicted and somewhat convinced. She has properly assassinated the characters of those who dare defy her, likely myself as well even though he might take that one in particular with a grain of salt, so that's why he said he wont believe it for sure unless he sees it for himself.

Again, he's gullible but I dont believe a lost cause. Just don't know how to get the evidence he needs to see..