These two options confuse me a lot like others. :P According to my analysis, the trending or top page shows the most upvoted and highly rewarded posts. And Hot page shows all recent posts which have a smaller amount of upvotes and rewards than trending page but have potentials to go on Top page.

If you look closely you'll see trending pages mainly shows highly rewarded but old post (even 24 hours old post), and the hot page shows mainly recent posts. It's kinda middle stage of "Trending" and "New".

This is my own perception, so it could be either right or wrong. Thanks for your question.