I believe it is seeing another’s soul at one’s own level.
Two people can meet by experiencing these levels - Physically, Emotionally, Mentally, and Spiritually.

When one is physically attracted to another, it’s through sight and touch in a three-dimensional world.

Being emotionally attracted to another is something you cannot touch or see. It is something beyond the physical body that you seem to be drawn to each other.

When you are mentally connected to another you feel comfortable, and you feel like you can talk about anything without feeling like you are being judged. You have similar interests and likes.

The spiritual is a contrast with the physical, a sense of a connection to a power with a reality beyond our physical realm. One's spirituality may also be the ability to connect to one's Soul Mate through a divine influence.