Ooohhh this is such a sweet ending with some real emotive moments. You fill it with the depth of history, of love and forgiveness, that explains the behaviour of Benjamin in the first half, and why he has put up with so much. The boundless endless light of love that will forgive and encompass all, you turn this into a sensitive love story, not a high vampire romance, but a story that despite supernatural elements, is about the people.

This bit

Everything happening now was revealed to me when first I laid eyes on you. But nothing was preordained. Each step, each turn in the path, you decided

and he loved her anyway, he gave her all the chances to cross him, in the hope she wouldn't take them, and stood by her anyway. The ending, which could be taken either way, is just perfect, allowing the reader to decide if in the end, she damned him in defiance, or because he had left her no choice but to accept his light.

Your use of german works well, you tie it into building on the first half, taking the small details and amplifying them to a ceiling-raising crescendo in the true finish the story style!