Do you mean that happiness makes us more beautiful? Haha, I think so, perhaps something like this was intended by the writer of this psalm.

Many "beautiful" faces we can observe, a good makeup, but I believe that there is no beauty that can be compared with that which emanates from the heart, from within, it is the most real beauty expressed in the light of our sight.

But for the pain of the heart the spirit is overcome

There is another biblical version that says: "the pained heart depresses the spirit".
When we are struck down by some situation that caused us pain, anger, frustration, disappointment, worry, our interior is discouraged, without strength, we walk a little discouraged, our face becomes that mirror of our heart, that smile is no longer , our gaze becomes a little sad, thus radiating what is inside.
I think it is difficult to overcome a contrast. Have you heard that phrase that many say "I laugh on the outside but inside I'm crying"? To that contrast I mean, I think it is a bit hard to cope, because sooner or later, that alarm is nothing other than our heart will clearly announce its status or condition.

@anaaguilar