Try it like a joke

You grab the pendant, and put into the light of the lamp to examine it.

Your teacher said it has a formula on it, you can see that too. But in the book you had found that the formula need some more words for it to work as crafted.
The book had some clues that lead to the final, complete formula.

You think of a way to try the formula and make it like a joke if it won't work.
"My teacher said there is legend about this one, as I can tell by the inscription. But I'm sure it's a fake."

Benedicte smile again and says
"The pendant is not a fraud, as it's really gold."

"And for the legend?"

"oh! many men tried it. At some times in the museum, it was a custom between the curators to try and act as if it worked."

"I'm sure that was fun. Please humor me, can we do that too."

Her smile fades for an instant and then she laughs.
"ha ha! well, why not, at least this custom was fun. But I won't do anything suspicious, so be warned."

I put the pendant on my neck, then I take a pose like a sorcerer for an incantation.
"neque ulla femina mihi resistet" (let no woman withstand me) "enim nunc et aeternum!" (for now and forever)

Did it work? What can I ask Benedicte to do to check that, and look like a joke if it didn't?