Heard this on Car Talk:

The CIA had an opening for an assassin. After all of the background checks,
interviews, and testing were done there were three finalists: two men and a
woman.

For the final test, the CIA agents took one of the men to a large metal door
and handed him a gun. "We must know that you will follow your instructions,
no matter what the circumstances. Inside this room, you will find your wife
sitting in a chair. Kill her!" The man said, "You can't be serious. I could
never shoot my wife!" The agent said, "Then you're not the right man for
this job."

The second man was given the same instructions. He took the gun and went
into the room. All was quiet for about five minutes. Then the man came out
with tears in his eyes. "I tried, but I can't kill my wife." The agent said,
"You don't have what it takes. Take your wife and go home."

Finally, it was the woman's turn. She was given the same instructions, to
kill her husband. She took the gun and went into the room. Shots were heard,
one shot after another. They heard screaming, crashing, banging on the
walls. After a few minutes, all was quiet. The door opened slowly and there
stood the woman. She wiped the sweat from her brow, and said, "This gun is
loaded with blanks. I had to beat him to death with the chair."