Rob Rausch is a man of his word ... because he bought Maura Higgins a luxury purse after promising her one on the 'Traitors' reunion show.

Check out these photos showing the 'Traitors' season four winner buying a Birkin bag Wednesday in New York City.

Rob was accompanied by comedian -- and "Therapuss" podcast host -- Jake Shane for his shopping spree at Hermes.

As 'Traitors' fans know ... during the reunion, Maura revealed Rob promised to buy her a Birkin bag.

Rob and Maura were this season's finalists ... and Maura trusted Rob until the end of the reality show, when he finally revealed he was a Traitor and took the prize money.

Maura said Rob promised he would buy her a Birkin bag as a way to make up for it ... and it looks like Rob is following through.

It's a win-win ... Maura is on the record saying a free Birkin is better than winning 'Traitors.'