Clear
An outsider would tell you it became clear when she kissed his cheek before grabbing his plate for lunch one day.
A Marauder would tell you it became clear when she approached him, slowly intertwined their hands, and joined the conversation like she'd been there for years.
Severus Snape would tell you it became clear when she blushed after his first polite greeting in six years.
She would tell you it became clear when she spied him by the lake in sixth year... alone, untouched from trouble, basking in the dying sunlight and sighing without a care in the world.
He, however, would tell you it became clear much earlier than the rest. To him, it was clear as crystal when he saw a small girl with bright red hair and teary emerald eyes on a crowded train platform.
Hey, all! I've really been away this time and there's no excuse. Unless you count Mulder and Scully and nine seasons of instant watching on Netflix. To those of you who are still reading this, I probably won't be updating very often. I've exhausted my creative resources haha.