If a guy said it to me on our first meeting then, yeah, I agree. Very superficial. But in the movie they had already been married and had a relationship. When he showed up at her door, she thought she would never see him again and was already TOTALLY in love with him. That's why she said it. Just him showing up was enough to sweep her off her feet. Like I said, very romantic and a total "movie" moment. Things like that don't happen IRL.