Handfastings  & Commitment ceremonies are not legally binding ceremonies. 
Handfastings are generally done 1 yr and a day prior to the wedding date itself. 
It was the early version of our engagement ceremony of today.

The Commitment Ceremony is along the same line as the Handfasting, the most
common use of this type of ceremony is for same sex couples who wish to express
their love, promising to love only their individual life partner and no one else.