What do you think this stare means ?

I think she is an actress. in this context it means nothing. she is paid to protray emotions in her facial expressions that may not be congruent to her actual feelings.

it is such a crazy skill to have. People who act for a living are overall so unqiue in that way.

however to play your game and not skip on your question and pretending she is not an actress --guess I would go with amused. she is amused.