Help me find the kdrama name, two sisters who are assassins

Korean movie , two sisters, spies. early 2010s or late 2000s

Its most probably a movie but could be a drama too

plot: two sisters who are assassins / spies.

time: 2006 or 2007 to 2013-2012

name : was something like " so lovely" or "so young" i vaguely remember