Argument over final dialogue: Did Daniel call 'tails'?

Caution: Spoiler!

Daniel flipped the two-headed coin in the bakery and Anna called "tails"--but of course Daniel couldn't come out and say it was a "cheating" coin. Anna obviously lied about the call.
Later she "comes around" and admits the truth.
In the final scene between Daniel and Anna, she flips a coin with the same premise: heads, I go with you; tails, you can go and I'll never bother you again.
Same slow-mo toss in the air, and Daniel smacks his foot down on the coin without looking at it: he's looking at Anna.
I could swear he said, "Tails."
Anna tells Daniel she loves him, they embrace, and the scene cuts to Daniel as a little boy, claiming that he will one day marry Anna. It is the smiling Daniel as a child, with that (cryptic?) little smile on his face as the movie fades to black.
There is a feeling of uncertainty, just as romance always has a kind of uncertainty about it.

My boyfriend argues that Daniel called "heads", that I heard it wrong, and that "heads" was the "only logical way".

I disagree. It would make more "romantic" sense for Daniel to do the very same thing Anna did; either they were both acknowledging the earlier scene where both Anna AND Daniel lied, and now the story was coming full-circle, or Daniel needed Anna to (convince/assure) him of her passion and love for him since he had renounced passion (or so he said) to become more "practical" like Anna, while Anna had become more capricious and willing to take the chance on love that Daniel had shown from the beginning--or perhaps it was both.

Obviously, I did not rent this movie, so I cannot just rewind it to play the final scene at the train station.

So my question then, is twofold: What DID Daniel call? Heads or Tails?

And, in the event that he actually did call Heads, can anyone see where Tails would have been the more "romantic" (and really the most honest) way for the movie to conclude?

My boyfriend and I are in disagreement over this. He thinks I am being unromantic, whereas I think I've given it more thought, which is quite contrary to his claim.

Someone please tell me!