these first 3 attacks can be forced and leaves her on 3 hits from staggering. if she doesnt do the 2nd jump attack its because you werent in the air for long enough. you can also choose to send the 2nd jump attack to the left but its generally harder to hit her i think. if she backsteps after the 1st attack you were too slow
as it was requested to be posted: after the first stagger, her attack where she slashes forwards 3 times, the slashes themselves don't have a hitbox anymore. You can still get hit by the square hitbox that is right in front of her though (or by just directly hitting her body) First 5s in the vid are before the stagger obviously