For english speakers it doesn't make sense because you use the verb "to be" for both situation: Example 1.: "I am fine, thanks" (it's a relative response becaus if you get a headache you might not be fine and your answer will probably change for "i'm not so good" etc.) BUUUT... Example 2.: "I am black" (unless u're Micheal Jackson, this state won't ever change) So.... this is the difference between "Sto" and "sono" in italian. "sto" = the 1st example - "Io sto bene" "sono" = the 2nd example - "Io sono nero". with the unravelling of the time you'll get used to it! Hope it helps! ;)
Unfortunately not how estoy/soy in Spanish or estou/sou in Portuguese. Examples:
Io sono malato = I am sick = Estoy enfermo = Estou doente
La cucina è pulita = The kitchen is clean = La cocina está limpia = A cozinha está limpa
Siete pronti? = Are you ready? = Están ustedes listos(as)? = Vocês estão prontos(as)?
sto is normally, sono is currently. Sort of. Did you follow the link I posted in another comment? stare and essere are tricky. 'stare' normally means 'to stay' and 'essere' means 'to be' but stare is often translated into English as 'to be' and then there's the idioms.