No Easement disclose by seller

We are about to sign P&S contract. Then from the documents the attorney faxed to us, we found that the seller/realtor did not disclose an easement. Before we made an offer, we specifically asked the realtor if there was any easement. She said "no" firmly. We already had our home inspection done and started mortage applicaiton process. Can we back out and sue the realtor/seller for our loss(inspection fee, mental commitment)?

Thanks.