Nudity is required.

"...that you strip of all of your clothes."

Some of the ladies gasp.
Some of them are shocked.
Two of them...nod approvingly.

"You are at your most vulnerable when you are naked," Wonder Woman explains, "You must be stronger than they think.
You must show no fear should you ever end up like that."

"If you can learn the confidence to fight in the nude, you'll be super confident when fighting under normal circumstances.
You agreed to follow my every command, so...strip."

Harley Quinn smiles as she strips off her clothes. She's always been a bit of an exhibitionist.
Starfire happily strips, having no body confidence issues.

Power Girl reluctantly strips nude.
Batgirl takes off her uniform, the multiple clasps and straps making it take a while.
Raven is nervous still, despite Starfire being so sure while she is naked.
Jessica Cruz takes off her ring and strips out of her civilian clothes.

"Don't get the wrong idea. I'm going to lead by example."

She strips off her uniform and stands with her arms over her head.
She's strong and defiant.

"Now then, we just need to do one thing," Wonder Woman says, snapping her fingers.

A group of Amazons enter, take all of the heroines' clothes and exit without saying a word.

"No temptation. No regret.
Ready to train now?"