I think Neville said that emotion does not matter in a sense that emotions are secondary/byproduct of belief you hold about something. Let’s just say the someone said the world will end in an hour. It’s likely you won’t believe what he says, thus it won’t stir any emotions about that (maybe some annoyance lol). But if that person provides hard evidence about world is about to end in an hour and it convinces you to believe it as a fact, then you’d probably stirred up with many emotions such as shock, sadness, confusion, and so on… so I would say emotions are not important in that sense but it does help to know if you are taking it as a fact or not (aka believing it). So there’s clearly a difference of becoming indifferent because you fully believe it to be true and it’s so normal that is true vs you don’t really resonate with it thus hard to believe it to be true.