Native speakers of English often have great difficulty in mastering the pronunciation of double consonants in Italian. One rule to keep in mind in learning correct pronunciation is that every letter in an Italian word must be pronounced. With this in mind, it logically follows that double consonants are pronounced longer than single consonants:

sano (pronounced sa-no) / sanno (pronounced san-no)

lego (pronounced le-go) / leggo (pronounced leg-go)

fata (pronounced fa-ta) / fatta (pronounced fat-ta)

papa (pronounced pa-pa) / pappa (pronounced pap-pa)

The double s in Italian has a different pronunciation than the single s:

casa (here the s is pronounced as in the English hose)

cassa (here the ss is pronounced as in the English house)