I don't think that's the case. Can you expand on this idea and provide an example of what you mean.

I think it depends on the type of emotion someone feels, just saying love and hate is not enough, when someone hates they can become the least sincere person in the world with the aim of destroy someone, but if we are talking about hatred towards someone for whom we previously had feelings, then all the little lies told in peacetime become a weapon and that is where hatred is born with pure sincerity imo.

I think this is because when someone is upset, they remove their filters and let their true feelings out. On the contrary, when it comes to expressing love, they often hold back from expressing themselves fully.