From the Movie True Grit the 2010 version. It means to show your toughness to any problem
You better show your true grit with that math problem.
The scruffy stuble on a freshly shaved nut sack.
"Im LaBeef, you wanna see my true grit?"
"My true grit itches, my rooster cockburn must be acting up"
"She wants LaBeef, hes got the true grit"
The following demonstrates true grit:
"LUCKY NED!" (fires pistol into empty mine).