The Gryffindors from their year are out for dinner. It’s five years exactly since their last NEWT, and tonight was declared a suitable date for their annual get-together.
Ron has told Harry, and only Harry, what he is planning to do tonight. He swore his best friend to secrecy, but he is starting to suspect Harry doesn't define "secrecy" quite the same way he does.
The others keep disappearing, for one thing, and none of them have come back yet. When Harry elbows Seamus into getting up, then drags him off the same way Dean, Neville and the girls went, Ron *knows* they've been plotting this. Harry is many things, but he's never quite mastered subtlety. Well, OK. Now he's alone with Hermione, which is obviously what they intended.
He'll deal with Harry later. For now, he has business to attend to. He slides off his chair, and drops to one knee.
He's not entirely surprised by the burst of cheering the second Hermione says "Yes".