I, Dobby ex-Malfoy, knew they were made for each other before anybody else. Including them.
I don't really know when I realised they were in love. It just sort of... happened, I suppose. But I do know that once I had an inkling that they might be perfect for each other, I made it my duty to make sure they realised what was right in front of them.
But I didn't reach THAT point immediately. No, I wasn't ever really thinking about them when I started my secret matchmaking business.