Hi hopesuccess,
Of course you can. :) You can sell designer/branded goods if you are licensed to do so by the parent company. You also have legal rights to resell branded items if you purchased them from a liquidator or a major department store, all licensed to sell / distribute these branded products. To prove that the items you are selling are purchased from an authorized seller or liquidator, you can request for an invoice and show a photo of such receipt in the eBay auction listing.
License holders protect their copyright only through distribution. If the genuine item you have is not sourced through its legal distribution channel, it ‘ceases’ to be genuine, it becomes counterfeit. Once eBay questions your goods suspecting that they are not genuine, you need to provide evidence that you have bought those items through a legitimate, licensed distribution channel.
Hope this helps and welcome to SaleHoo! :)