Need advice - First Home Buyer

Hi. First home buyer here. We've put in an offer for a unit that we liked. The REA is coming back saying there's a higher offer. We've hiked our offer twice already as this house ticks a lot of our boxes and there's not much options in the market for our relatively low budget. We do have an upper limit in mind and we'll stop there and let go of the property.

Question to this hive mind is - Is there anyway to confirm that there's an actual genuinely interested party? And the REA is not just trying to rip us off?

For context, this unit has been advertised for several months now and has also been passed over in an auction. Hard to believe so much interest all of a sudden.

Thanks for any advice.