[Part of him's a little hurt by his recollection's being questioned. But he understands the necessity of it, with all the tricks that this place plays. He tries to keep up a smile as he continues.]

That's something I can't just forget. [He closes his eyes to dismiss the painful electric memories, and opens them looking back at Katara.] And I still remember waking up for just a few moments and seeing just your face. That smile was the best welcome I could have asked for. [The smile has become more genuine by the end of the sentence.]