They retconned in a past for them, which very literally went against the one displayed on the actual comic page.
I believe in the original, Ororo saved T'Challa's butt from some wild animals or something, they exchanged some basic greetings, and Ororo went on her way.
In the retcon, T'Challa saved Ororo, and then they went on a zomgspiritquest together, fell in mad, true, passionate love, then separated and didn't communicate with or speak of each other for years before suddenly simultaneously deciding it was time they married each other.