La mia bellezza is an Italian equivalent of the English phrase "my beauty." The feminine singular definite article, possessive, and noun translate literally by word order into English as "the my beauty" since Italian differs from English in requiring a definite article before the adjective. The pronunciation will be "la MEE-a bel-LET-tsa" in Italian.
[La] mia bella is an Italian equivalent of 'my beautiful'. In the word by word translation, the feminine definite article 'la' means 'the'. It doesn't have to be used, because it's followed by a possessive. The feminine adjective 'mia' means 'my'. The feminine adjective 'bella' used as a noun 'means 'beautiful [one]'. The phrase is pronounced '[la] MEE-ah BEHL-lah'
"Beautiful night" in English is bella notte in Italian.
"We are very beautiful!" in English is Siamo bellissime!in Italian.
"Beautiful horse" in English is bel cavallo in Italian.
"Beautiful woodland!" in English is Bel bosco! in Italian.
"Beautiful walls!" in English is Bellissime mura! in Italian.
"Beautiful mountains!" in English is Belle montagne! in Italian.
"Beautiful mommy!" in English is Bella mamma! in Italian.
"Beautiful moments!" in English is Bei momenti! in Italian.
"Beautiful nephew" in English is bel nipote in Italian.
"Beautiful disaster" in English is bel disastro in Italian.
"Beautiful dream" in English is bel sogno in Italian.
"Beautiful Rome!" in English is Bella Roma! in Italian.