In many paths people believe in the concept of a soulmate. It is believed to be the person (the soul) that completes your own. In some traditions the belief is the following:
The soul is divided in two after the physical death and it is reborned in two different bodies that are considered soulmates. These two people will meet at some part in their lives.
The shine in one's eyes is a way to understand if they are your soulmate.
Also a feeling of peace and compliteness is present.
However my opinion is that when someone is right for you, you just know it. But if you want you can use one of these techniques to help you:
However I wouldn't reccomend past life work for this particular cause it can be confusing.