I don't think Petra makes annoucement of events like divorces! I don't remember it was the case of Hamza's divorce ;-)
If it's the FB account of Sara Kabbani from long time so why not to trust it?, I think she's daring the jordanian royal family and made the announcement herself because she was hurt!
"It is very important to generate a good attitude, a good heart, as much as possible. The short-term happiness and the long term one at the same time, for you and for others will come." Dalaï LAMA