It seems that if you have the trust meter maxed out before Guilmon initiates her final conversation starter, she will then skip to a different dialogue once that trigger is supposed to happen - specifically, the one where she asks if you accept her feelings, as if she's already admitted them to you. It seems that dialogue is not limited to only being accessible after you've asked her at full trust to tell you how she really feels.
I can see the JSK Studio influence here, so I feel I should point out that in JSK's later games, the player's last available dialogue choices are left permanently accessible after you unlock the ability to say them. In this current version of Misunderstood Mon, you still only get to say two of your final dialogue choices before the player character declares "that's enough questions for now", thus locking you out of the love ending for the rest of that session since no more choices appear after then. If this is tweaked to allow the last choices to stay available, any player who's made a dialogue mistake along the way can still save their run, by still being allowed to raise the trust to max and pop the question.
One other critique that's possibly impractical, given the hand-made nature of the game's animations - personally I feel like if the player has accepted Guilmon's feelings and can access the love ending with the End Game prompt, Guilmon's expressions should change to be happier both in normal gameplay and during the sex animations (which would be the hard part), and sex requests would be met with enthusiasm rather than nervousness. (This also happens in some JSK titles, or is placed in an "extra mode" after getting the main game's love ending.) It's perfectly fine if this can't happen though - I look forward to seeing how something like this could make it into a future game! Honestly I've kinda been wanting a JSK-style furry porn game for years now, and this really scratches that itch. ❤️