Steve Rogers
"To cherish everything we have together because I know it can be lost in a moment. To love you with everything I have because you deserve the best of me."
Tony Stark
"To appreciate you more often, to shower you with the affection that you show me and to make your bedroom experience amazing. . ." He clears his throat. "Sorry, um, I mean it. I promise to show you that I love you and to appreciate all of the little things you do for me."
Bruce Banner
"To show you the best you can be because you showed me the best in me. The shower you with the affection and admiration that you've shown to me. To love you with no doubt even with my demon in the back of my mind. "
Thor Odinson
"To show you your unconditional love. To show you that the universe is incomparable to you, nothing in any realm comes close to showing you how much you mean to me. So, I shall promise only my best to show you this."
Loki Laufeyson
"To love you as you have loved me. To show you that I am thankful and blessed to know your love. You have been there for me for each moment I was weak and, thus, I shall spend all of my time in an attempt to show you the same."
Clint Barton
"To love you even in my last moments. To show you what you've shown me and to make our time happy and full of nothing less. Oh, I'm not good at saying things like this. I just want to let you know I love you. No matter what."
James "Bucky" Barnes
"To stick with you, even in my weakest moments. I owe you much more then what one lifetime can show but I will try my hardest to show you everything I can. I promise my love will be unconditional."
Sam Wilson
"To spend every day making you happier than the last. To love you with all of my heart and cherish every moment with you because they mean everything to me. It'll take me forever to show you just how much and I plan to do the best I can to prove it to you. I love you."