If they killed you first, then that means they loved you more than you loved them back. You can also figure out (in the last second of your life) whether your mom loved you more than your dad or not.
Always watch out for family members, you never know when one of them decides to express their love towards you.
If you're the last person alive on the plant, congratulations! Nobody loves/loved you.
That last person alive will most likely be Mithrandir.