The whole point of Hayate was making fun of manga tropes and misunderstandings for comedy, while very purposefully not breaking any of the tropes it was making fun of. (example, last chapter's bath house scene) I don't expect anything different from this.
Hayate also was known for teasing...
They've been living together for less than 12 hours. She showed up at Nasa's door at midnight on his birthday, and this is the next morning.
She also said she fell in love with him but when and how was a secret. However, she knew where he lived, and his birthday so this couldn't have been...