Are realtors liars?!!

We’re working with a realtor to rent a home. We’ve found 3 great homes. First one someone rented before us second one same thing! Third one we went to see applied for 2 hours later. I confirmed with my realtor no other applicants were in, he even called the other realtor... supposedly. Well guess what miraculously someone had an application in front of us. I find it sketchy he had someone else come see the home right after us. Keep in mind this is our realtor and he has nothing to do with the house. He told me the couple took another home. I think he’s lying. He pretty much told me I’m screwed because we need a place by December 31. Are realtors notoriously liars? Is that common just for business.

ETA: for those wondering why I used a realtor for renting. They have connections and with the crappy selection I see on Zillow they have many more houses to show. They’ll do the negotiating and start the application part. They also can get quick access for viewings whereas it can take me a few days.