Interview questions based on past behaviors are good to ask. Why? Most retail interviews are built on nebulous questions about the future. "What are your goals in five years?" Nobody fails that question, which is exactly why it tells you nothing. Past behavior predicts future behavior, so interview about the past.
Here are the two questions I use.
First: "Describe a sure sale you lost, and why you lost it." Then be quiet.
Don't fill the silence when they stall. If they need a moment, say "take a moment," and wait. What you're listening for is whether they can name their own role in a customer walking: they said the wrong words, they confused the sale by adding one more item at the end, they buried the customer in coupons and rebates. You're testing for honesty and self-awareness.
A candidate who has never lost a sale, or who lost them all to "cheap customers," is telling you how they'll explain your empty register later.
Second: "Tell me about a time somebody came in to buy X and you sold them Y." This one tests whether they can compare and contrast on their feet.
Online, there are a hundred thousand versions of whatever your shopper wants, and the odds you stock the exact one are slim. The associate who can say, "Would you be interested in something the same or better?" saves that sale, because a customer who drove to your store is usually open to it.
The associate who can only find the exact item is a search bar with a name tag.
Yes, hiring is hard right now. It always has been. But these two questions, asked patiently, sort the people who can think on the floor from the people who will need you standing next to them for every sale.