Bucky had to think about it. How could he prove something so massive and impossible? A thought came and he wondered if it would be enough. He didn't want to just make her angry or even more wary of him. Or to hurt her. But he couldn't think of another way.
He sang it softly, his voice rougher than the song deserved, and some of the pronunciations were just a little bit off due to a lack of recent practice. But the lullaby would be recognizable.