Closely inspect them

"This is odd," Kamek said, looking at them more and more. "They don't seem to have any differences from what I see. What about you?"

"Umm... well..." Bowser found his body drenched in sweat, unable to tell even the slightest difference between the Peaches. This was the woman he loved, the one he dreamed to marry so many times in the past, if no one could figure out the difference he should be able to. There must be, there must be some way he could tell...

"I think it's impossible to tell from this distance," Bowser said. "We need to take a closer look."

"Ew!"
"Pervert!"
The Peaches glared at Bowser and covered their chests, expecting him to inspect them in "that" way.

"It's just to find the difference between you two!" Bowser blushed and waved his hands. "I mean... I won't... well um... you see..."

"Sire," Kamek said. "Let me look at them."

"Yes please." Bowser looked away and covered his eyes, although he occasionally took a few peeks.

Kamek opened the cage and took a closer look at the Peaches, leering at them through his thick glasses. A closer inspection didn't seem to change anything, in fact it only reinforced how similar the two looked. When even the tiniest scratch seemed to be reflected on both of them it felt like this idea was all pointless.

"Sire," Kamek said. "I regret to inform you that the close inspection has failed. I still can't find a difference, they are virtually the same."

"I see." At first Bowser was a bit disappointed. If they were virtually the same, he may never be able to tell the real one from the fake. He'd have to marry both of them to make sure he got the right one. Marrying two Peaches...

"Actually," he said. "This isn't a problem at all. We can work with two Peaches."

"Um sire..." Kamek looked back towards the cage and back to Bowser, a worried look in his eyes. "About that..."

"Two Peaches is not enough! With your magic I can have three Peaches, four, I can fill this whole room with Peaches!"

"Sire..."

"I can have a Peach by my bed every time I sleep, a Peach to bathe with, a Peach to eat with, a Peach to conquer lands with. A Peach here, a Peach there, Peaches and Peaches everywhere! Peaches Peaches Peaches Peaches Peaches Peaches Peaches Peaches!"

Kamek decided to close his mouth. How was he now supposed to say he accidentally left the cage open and the Princesses escaped?