Wanting to sell 0.18btc for paypal. Trusted only or you send first.
You are not sufficiently trusted for it to be a good idea for them to send first so if the other person is not sufficiently trusted for you to go first then you should send first to someone trusted and then once your trading partner sends you the PayPal then you have that trusted person send the BTC to the person you are trading with.
This would of course not do anything to protect against a PayPal chargeback however neither would having the other person sending first and then you sending the BTC shortly thereafter.