What is the proper way to display the price of your in-app purchase in multiple currencies

Question

What I'm trying to do is display the total cost of an in-app purchase when a button is tapped. For instance, one of my in-app purchases costs $0.99 US dollars, but what I want is to display the proper amount if someone is buying it outside the US. For instance, if someone is buying it in Italy I want them to see the equivalent of the .99 cents, which in this case it would be €0.84

The following code only shows and formats the 0.99, it does not do the conversion to the current currency.

What am I missing?

What is the proper way to display the cost of an in-app purchase?

@IBAction func showPrice(){
    var productInfo:SKProduct?

    for product in IAPManager.sharedInstance.products{
        productInfo = product as? SKProduct

        let numberFormatter = NumberFormatter()
        numberFormatter.formatterBehavior = .behavior10_4
        numberFormatter.numberStyle = .currency
        let inAppPrice = numberFormatter.string(from: productInfo!.price)

        print("Price is: \((inAppPrice)!)") // output for US - Price is: $0.99
                                            // output for China - Price is: CN¥0.99
                                            // output for Italy - Price is: €0,99
    }
 }

EDIT: Based on the documentation my code should work.

EDIT: Just for reference, here is the working code: Thanks to @rmaddy and @dfd, .priceLocale and testing in a sandbox is the key.

@IBAction func showPrice(){
    var productInfo:SKProduct?

    for product in IAPManager.sharedInstance.products{
        productInfo = product as? SKProduct

        let numberFormatter = NumberFormatter()
        numberFormatter.numberStyle = .currency
        numberFormatter.locale = productInfo!.priceLocale
        let inAppPrice = numberFormatter.string(from: productInfo!.price)

        print("Price is: \((inAppPrice)!)")
    }
 }