It means to accept yourself completely enough to accept someone else. You have to love and accept yourself before you can love and accept someone else. The sharing of that love and acceptance is the key to continued growth within a relationship.
It is finding the only person you can be your most vulnerable, trusting and sharing the most intimate thoughts with as well. It is knowing someone that completes you.
It is a very strong sexual attraction.
Well I might also say a very strong emotional attachment.
to consciously nurture the well being of life