Being told what is to know

After a visit to the human world Starlight kept thinking about the fun times she had there. But for a reason she can't stop thinking of one person there. Someone who's cooler than anyone she every met, someone who's as powerful her, someone who was nice enough to let her stay at her place; Sunset Shimmer.

With no advice about it from Princess Twilight she went to Rarity, who told her what she needed to know. Twilight knew she needed Starlight, she also knew, as a good friend she had to let Starlight make her own desertion. So she let Starlight visit the human world once more for as long as she desires.