Buying a house/property that is in the first stage of probate?

We made an offer on some property and the estate was just opened tuesday. They have not filed any paperwork yet. they are the only known heir and their name was on the deed also as joint ownership. They want us to pay earnest money, which we don't mind but we do not want to give anything unless we know for sure the property will be ours. we are in need of some information on what we should do.