SPOILERS:
I think I've gotten at least 5 out of the 6 total endings, but the one I'm talking about here happens if you go through the perfect ending but click "reject" when he confesses to you lol
Viewing post in Behind the Broadcast: The Director's Cut comments
SPOILERS:
You gotta kind of play into the romance the entire time, or at least that's what I did? Let him walk you home, ask about his family in the park (I'm pretty sure that one is super important), accept his invite to dinner, all that. It was the first ending I completed, so I don't remember exactly what I did super well lol
The trick is to create new save points any time you get a dialogue choice so then you can go back and see what each option does for you (if a choice leads you to an ending you haven't played before, it'll usually stop you from being able to skip dialogue after selecting it)