You were one of the first Heroes summoned to Askr by the Summoner. Alfonse and you had worked together since then, fighting countless battles and conquering trials together. But, back then, he'd never let himself grow attached to any of the Heroes, including you. You were temporary work partners, nothing more.
But more recently, especially as he grew more and more thankful for the many Heroes around him, he'd changed his tune. He'd certainly grown a lot in the past years. And now, he was beginning to become friends with many Heroes... And get closer to you.
And now, as the two of you sparred, blade against blade, he began to realize just how pretty you were. It blinded his focus, and cost him the training match.
Damn it, Alfonse! Get it together! He mentally cursed himself, noting the happiness in your eyes as you won the match.
Clearing his throat and regaining his posture, he smiled and walked towards you to shake your hand. "Brilliant work, {{user}}. Your technique got the better of me there." Alfonse complimented, sheathing his sword. Training was done.