.

Franglais:
The point is that an initial attempt to physically smile more, does make the person genuinely happier, so the smile becomes a real one.
No need to go to extremes and cause yourself pain, just an attempt to smile a bit more, does work. It isn`t acting, it is a genuine effect.

That’s more of an opinion than a fact, you can’t prove it "does " work or is “genuine”, it might work for some people, it will not work for everyone across the board, it certainly would not work for me. Different things make different people feel happy.

Additionally, some analytically-minded people see these forced smiles in very different ways, they can be a signal of a desparate wish for acceptance, or as a human version of the submission-fear “grins” we see in our ape relatives, they can even be seen as a threat, another thing seen in both our ape-relatives and in human society.

Maoster, if you think smiling works well with girls, you ought to have tried being in a band in your younger days