I'm surprised no one has responded to your question yet...
I think part of that is the issue of safely getting money and not getting scammed. Unfortunately, it's a difficult challenge.
To be absolutely safe, what you could do is seek out an Escrow company where you would set up an account with them, the buyer deposits money to them. You would proceed to transfer the domain to the buyer. Once the buyer confirms that they have received and control the domain, the funds would be released from escrow to you.
This protects both parties from scams. If the buyer deposits money to the escrow company, they can't get those back until you invalidate the transaction ... and you can't get those funds until the buyer has confirmed that they have the control.
Outside of using escrow, I think you'll run into issues with trying to do this without being scammed. You will unfortunately risk the possibility of the transferring the domain and then the buyer issuing a chargeback, causing you to lose out on the money and lose out on the domain as well.