What should i wear with this cardigan.?

The cardigan would look the best with black slacks or dark blue jeans. I wouldn't recommend a loose fitting and/or long skirt because the cardigan looks to be loose as well and too much flowing fabric in one outfit does not work well, but a pencil skirt with leggings would be a nice ensemble. Darker colors too: blacks, dark grey, dark blue. Whatever looks good to you.