Rei is still surprised.
Her stiff expression slowly changes into a smile.
Rei relaxes.
Trajan: This shot makes me smile.
BiQ: And never again could Gainax or Khara top or even reach again this very first rendition of this ultimate heartwarming.
Leighton: My eyes watered at this scene - I actually felt happy at Rei's first expression of joy (in Shinji's presence) as a result of Shinji's care for her.
Additional Commentary
EvangelionFan:
Rei: "... So he just wants me to smile? If that's what it takes for someone to get a nap around here then fine, I'll comply... but there had better be a good bed and breakfast deal in it."
Kendrix: Congratulations, Shinji! You have been welcomed into the small circle of people who are allowed to see that smile.
The 'blush lines' (The Rebuild and death and Rebirth renderings of that scene make it more obvious that this was meant to be a blush) indicate that this smile is genuine, i.e, she's not doing it just because he told her to, but mainly because the afore mentioned realization.
Needless to say, this is the point where they fall in love. This is, like many other things, emphasized in Rebuild, where they go as far as, for all intents and purposes, holding hands.
thewayneiac: Of course we'll have to see the two remaining installments to know for certain, but I agree they are in love in Rebuild. But if you are saying that they fall in love at this point in the series you are probably overstating it, at least on Shinji's part.
