Hello! We posted an FAQ yesterday clarifying that there are two criteria for successfully asking a love interest to the Spring Fling: a minimum number of dates and choosing enough “good” dialogue options. The former is tracked in the notebook with the apples (half an apple per date), and the latter is revealed to the player through the love interest’s responses and Cassandra’s debriefs after each date.
Kipperlilly’s route is definitely the toughest one, but for good reason. Think about what Kristen’s established relationship is with her. The rejection dialogue clues you in to what’s important to her and why she’d hesitate to accept your ask!