His girlfriend owes him $2000. Should he be concerned?

“My girlfriend of 4 months owes me $2,000 because I helped her cover her rent for a couple months. She now has a job and just bought a new car, even though her old one was working fine. I asked her why, and she said she wanted to treat herself and that she’ll pay me back in the future.
I don’t need the money now, but I’m worried about this becoming an issue. What do you think?”