If that 3500 lbs is the trailer GVWR, great, and go have fun. But if it's the unladen (dry) trailer weight, then you need to be concerned with how much stuff you load into the trailer, cause it is going to approach 4500-5000 lbs quickly (even though you probably don't believe that right now). Further, the Sorrento's trailer towing capacity decreases as you add weight inside the SUV, so multiple passengers and their gear can take that 5000 lb tow rating down to 4500 or so. So can factory options on the Sorrento, anything above and beyond the base model specs.
You probably won't enjoy towing a trailer that weighs an actual 4500 or so lbs behind the Sorrento, even though that is acceptable from an engineering point of view.