So "strong" that she was poorly written. Probably the least interesting, undeveloped character in the old films.
She was an emotionless shell of a...."human" being, although she might be a socialpath. She is given no reaction scene or developed character trauma for any of the following
(1) her home planet (not house, not family, not city, not her dog; HER PLANET) is destroyed in an unprecedented display of power in front of her
(2) at some point she must realize the man who tortured her and destroyed her planet is her father...in ROTJ.
(3) she is made into a scantily clad slave-girl by a disgusting worm alien pervert, who may or may not have raped her.
(4) And don't forget that great moment when she kissed her own brother romantically.
The only time she is ever given emotion is upon witnessing Han get frozen in carbonite. Han: the guy who led her on and then didn't even return her "I love you" properly.