[There's a strangled, 'hwah!' sort of noise at the headpat and her eyes fill with tears almost instantly]

Thank you very much! I-I promise to be the best friend I can be! [She even goes so far as to throw her arms around him, sniffling as she tries to hold back from outright sobbing on him. After a moment though she remembers why he's here in the first place and lets him go, eyes wide]

I-I'm sorry! I shouldn't have-- I didn't get permission-- Um, um... I have to p-put this glass away and, um... Y-you didn't just come here to c-call me a friend, right? [Something about an initiation, right??

Though maybe she shouldn't have reminded him of that in the first place.]