Hi to be short, in a scale from 1 to 10 (like at school) Sto male = 3 Mi sento poco bene = 4 (四) Così così (马马虎虎) = 5 → Abbastanza bene = 6 Bene = 7 Molto bene / benissimo = 8 9 = we use analogous expressions like mai stato meglio (= never felt better) splendidamente mi sento in splendida forma and anything which could express such a wellbeing.

"Abbastanza bene" means good/well/fine enough or quite good/well/fine, while "benissimo" means extremely good/well/fine. So "benissimo" show the better condition. For example, if you ask "come stai?" (how are you?) and I say "abbastanza bene" it means I'm quite fine, but if I say "benissimo" it means I'm extremely fine. Hope it's Clear :)

let's say that the meaning is the same but the substantial difference is that in the first case it is quite good but it could be better. in the second case if I ask you the question, for example: how do you feel today? today I'm fine, I'm at the top I'm really charged. in the second case it is more positive. abbastanza bene translates as i'm fine, it's ok I'm not complaining. benissimo is a superlative of bene so it's more like: how was the football match? very well, we won.

let's say that the meaning is the same but the substantial difference is that in the first case it is quite good but it could be better. in the second case if I ask you the question, for example: how do you feel today? today I'm fine, I'm at the top I'm really charged. in the second case it is more positive. abbastanza bene translates as i'm fine, it's ok I'm not complaining. benissimo is a superlative of bene so it's more like: how was the football match? very well, we won.

Benissimo. As far as I know, abbastanza bene means fairly good/well. Benissimo, on the other hand, means very very good/well.