Wedding Vows he says to you:

Dean:
"Y/N, we may not have met on the best of terms, you being attacked and all. The instant I saw you, I knew you were the one. We've had three years exactly to love each other and it worked. I love you more than I've ever loved anyone. I was extremely nervous asking you to marry me, even more nervous than hunting certain monsters and demons. I was worried about your response, but you said yes. You agreed to marry me. Thank you. I love you."

Sam:
"Y/N, I've never really had any good things in my life, but then I met you. You were the best thing that ever happened to me. I truly love you, and I'm pretty sure you love me too. I was really happy when you agreed to marry me, because then the one amazing thing I've had in my life, will be with me always. I love you."

Castiel:
"Y/N, me being an angel off and on has been complicated. I've never been very romantic, but you still liked me for some reason. I started to get quite fond of you too. Everything started out strange and awkward. First date, first kiss, etc. Yet, you still loved me. And I, love you."

Adam:
"Y/N, I know we've had a rough relationship. Things didn't go quite as I planned them to this past few years. But, even though all the rough times, I still loved you. And for some reason, you still agreed to marry me. I'm really grateful for that and to be here, now on our wedding day, getting married to the most wonderful women ever. Love you."