Need advice if safe for my pickup to pull a heavy 5th wheel

How could anybody declare this would be "safe" for somebody on the net?
If I had owned the truck for years, worked with it, I would have no issue moving the load once. I'm not saying I'm a better driver than OP, but I know I can't count the number of trips I have made well over the GVWR, and GCVWR of many, many vehicles.
The fact the OP is on asking advice from strangers tells me he does not have the experience, but might be he is hoping to be told NO! so will come up with another plan.