I'll nevet forget, on one of my playthroughs around when dawnguard first came out... I was retiring a character, and thought , "Why not? He deserves it." So... I went through all these careful preperations, and went back to the place where you read the elder scrolls. I got her to stand precisely in the middle of the light and proposed to her Skyrim style... and she refused! That character is now probably a hermit living alone in a cabin in the middle of some forest. I laughed my ass off for hours though, it was entertaining that there is someone in the game who can tell the dragonborn "No".