Wow, the first news article I've read in a while that actually makes some sense:
Daily Mail: 'Trump blew whistle on Jeffrey Epstein'; Pedophile's threat to expose President 'as a financial fraud' after he 'stole' his $125M mansion led to then-tycoon outing the pedophile to cops
Reality truly is stranger than fiction...
Update: Just realized this was published back in July (I stumbled across it presented as a breaking news item).
Anyway, this clarifies a lot of things for me. If I had to guess the back-story to the Trump-Epstein relationship, Epstein made friends with Trump with intentions to target him as he targeted many similar wealthy and influential individuals. He partied with Trump and vice-versa. At some point, he made "the offer" to Trump. I think this is why, later on, Trump made the remark about Epstein liking some women "on the younger side." I think Trump immediately understood what was up (peddling underage women to a wealthy man as blackmail bait), and decided that it was time to turn the tables on Epstein. One bad turn deserves another.
This is all in my opinion. The facts are difficult to pin down due to the extreme scarcity of tangible evidence.