Question for a landlord

[Holly Murphy]

I have a friend that has been living in the UK for over 20 years and now wants to return to the US with her UK spouse and family.  She doesn't really have a credit history in the U.S. and I believe she and her husband bought a property, so they don't have a rental history that they could get references for.  She wants to rent first and eventually buy.  What would you be looking for to gain assurance of her credit and character to be able to rent a house to her?  (Looking for ideas to give her)  Thank you!