Does She look prettier when she's in love?

It is not only possible, but it usually happens. There is a very strong connection between the body and the mind.

The connection is called psychosomatic, and usually, we think of it in terms of illness. A person’s mind can influence his body to make him sick or well. A sick or healthy body, in turn, can influence the mind.

The connection is not mysterious. It is based on the nervous system and the different chemical hormones that flood the body at the command of the mind. 

These hormones direct the actions of glands and blood vessels.

When Selma falls in love, her emotional reactions cause an unconscious response in her body and in her body language. Her muscle tone is heightened, and the sagging lines in her face are tightened up. Her skin may flush more readily, and her eyes may sparkle while her poor posture disappears. A number of courting signals are released at a time like this, and all in all a body language message is sent out: “I am attractive and desirable.” The message influences the fact. Selma becomes prettier.