I think that says a lot.

I find this particular moment very romantic. This quiet and even 'mysterious' person is first introduced in this dramatic action of 'turning in haste'.

I can imagine the scene.
If I were a film director I would make this moment one of sheer romance, that would leave an impact on the mind of the audience, of something profound in his look, and words, after that hasty turn :)

Marinne was probably not looking, otherwise she would have seen 'that something, in his eyes'.