221 g how to prove domecile without long stay in us

my immigration visa interview done under f2a category for me and my doughter who is 3 yrs old.

visa refused, with white colour 221(g) paper.

my wife who is petioner stayed maxium time with me in india,without long stay in usa,how she can show domicile to fullfil requirements for 221(g).

if she buy a property in usa .it can help?