Hmmm....she probably means she will only say it one time. That's the English sense of the sentence.
On the other hand, "once" is the Spanish word for "eleven". So, maybe we can get her to say it ten more times? I am not sure how audience participation works here on DA, but it's worth a try.
(I once said something only once, but that is because the balloon I was using to breathe from ran out of helium.)