Answer:
Bravery a trait allowing someone to face danger, to do the right thing without showing fear, no matter how terrifying or difficult it may be.
Bravado is a show of courage that may seem brave but is actually unnecessary and dangerous.
Marie Colvin is pointing out that the line between bravery and bravado is thin. We have to carefully evaluate the situation and determine whether it's the matter of bravery or bravado, whether it's worth the risk or not. Many war journalists before Colvin, who lost her life on the battlefield in Syria herself, died as a result of poor judgment.