My russian dwarf hamsters wont mate plz hlp?

i have a 1 yr old albino russian dwarf hamster and a female 6 month oldish russian dwarf amster yes i have cheack they are male and female but i have put them together a month now but they wont mate they wont fight ether ther like best friends but i realy want to mate the plz help the housing and wvery thing is right what should i do