I'm here to review your story for The Take It Seriously Challenge! I'm sorry it took me ages to get here, but life has been keeping me pretty tied up. I'll break this review down into the categories I'm using to judge each entry. :)
Rarity - Luna/Ginny and Luna/Blaise are both fairly rare, although I have read both pairings before. I even have a Luna/Ginny one-shot on my page. :) But I liked that you included two rare pairs.
Editing - I thought this was pretty good, but one thing that I think you might want to watch out for is repeating names too often throughout the story. For example, in this story, you identify Blaise by name 18 times in about 800 words. I know you were trying to identify who was speaking, but it was just a bit much particularly considering there were only really two people talking...Luna and Blaise. It wasn't a super big deal, but it did throw off the flow a bit for me.
Flow - As I mentioned a bit in the section above, there were some areas where the flow was thrown off for me, but overall I thought the piece moved along nicely. The progression of Blaise's feelings from beginning to end were nice.
Emotional Impact - I did feel a bit detached from Blaise in this piece, but I think that works to your advantage. I don't really picture him as the crying, super emotional sort, so I thought that fit his character well. Maybe a few more descriptions about his inner thoughts would've helped to tie it together a bit more.
Plot - The plot worked nicely. You did a good job of showing the stages of the wedding and how Blaise is feeling throughout. It moved at a pretty natural pace too.
Characterization - I thought Blaise was characterized well. He comes across sad, but sort of detached and protecting his feelings. Luna was a bit OOC for me. I think she was sort of missing that light, floaty, whimsycal persona she carries in canon.
Overall, I thought that this was a nice one-shot and a good look at Blaise as a character! Thanks for entering the challenge!