And then he gives me a smile that just seems so genuinely sweet with just the right touch of shyness that unexpected warmth rushes through me.

The line captures a sudden, involuntary shift from guardedness to vulnerability: a small, “genuinely sweet” smile—tempered by shyness rather than bravado—breaks through the narrator’s defenses and produces an immediate physical response (“unexpected warmth rushes through me”). Collins often renders adolescent attachment not as grand declaration but as bodily sensation and fleeting gesture, emphasizing how intimacy can arise in the smallest moments even amid fear or uncertainty. The phrasing also highlights the narrator’s surprise at her own reaction, suggesting emotional awakening and the destabilizing power of tenderness in a world where trust is risky.