Bello vs. bellissimo
In Italian, both 'bello' and 'bellissimo' are used to describe beauty, but they differ in intensity and usage.
Bello
'Bello' is the standard adjective for 'beautiful' or 'handsome' in Italian. It's commonly used and can describe a wide range of attractive things or people.
Che bel vestito!
(What a beautiful dress!)
Marco è un ragazzo molto bello.
(Marco is a very handsome boy.)
Oggi è una bella giornata.
(Today is a beautiful day.)
Bellissimo
'Bellissimo' is the superlative form of 'bello', meaning 'very beautiful' or 'most beautiful'. It's used to express an extreme or exceptional level of beauty.
Il panorama dalle Alpi è bellissimo!
(The view from the Alps is absolutely beautiful!)
Hai visto quel quadro? È bellissimo!
(Have you seen that painting? It's gorgeous!)
La Fontana di Trevi è bellissima di notte.
(The Trevi Fountain is stunning at night.)
Summary
While 'bello' is used for general descriptions of beauty, 'bellissimo' emphasizes exceptional or extraordinary beauty. 'Bello' is more versatile and common in everyday speech, whereas 'bellissimo' is reserved for expressing strong admiration or awe.