How to get commitment from a renter contingent on our closing

[Rachel Palmer]

We are scheduled to close on a new home June 15th; so I listed our current property for rent available July 1st.  We found a good renter that is very interested but I don't want to sign a lease until we are sure of closing.  What would be a good way to get a commitment from them contingent on our closing.  I don't want to turn down applicants and then have these renters back out last minute.