Hanlie Lategan, 52, was found dead in a stream in Randfontein, Gauteng, 20km away from where she arranged to meet potential home-buyers from Cape Town on Monday.
CCTV footage from Krugersdorp Private Hospital shows her withdrawing cash from an ATM before being driven away. She had arranged to meet "potential buyers".
Her cellphone and bank cards were missing from her purse.
The Gauteng secretary of the Institute of Estate Agents, Rachel Gouws, said: "We have three to four seminars a month. Of the 50 people who attend, up to 30 tell us of security incidents."
She said many agents no longer wore jewellery when they met buyers, and she recommended that they meet clients in public spaces or take a colleague with them.
Glen Norton, CEO of the Remax estate agency for which Lategan worked, said: "As agents, our biggest risk lies in appointments with buyers, especially unknown first-time buyers."
Lategan's daughter, Joane van Heerden, said: "We don't know what happened. We just want her killers caught."