Sponsored Adverts on shared listings. Do I get the Buy Box?

If I pay for sponsored adverts on product listings where there are other third parties or Amazon direct, am I assured of the buy box for every paid click? Also do customers still see that other sellers are available to buy from?

It’s more the other way round.

Your advert won’t show unless you have the buy box at the time.

Once a customer clicks on your ad, they will be able to see other sellers but of course, the buy box will get the majority of the orders.