None. There is no relationship between the two of you.
As there are no blood ties there would be no relationship.
They're cousins.
They are distant Cousins
If it is not your common grandparent, there is no relationship.
She has no relationship with your step-daughter. They do not share a common ancestor. If you adopt her, they would become second cousins once removed.
dappy and tulisa are cousins
Cousins
They are cousins.
You are First Cousins
You are cousins
They are of no blood relation. But they are cousins by marriage or 'step-cousins' as such.