Learn Italian: Il fiore è rosso e molto bello. - The flower is red and very beautiful.

Nouns ending in -e can be either masculine or feminine, so you have to memorize their gender as you learn them. In this sentence, the word il is your clue: fiore is a masculine noun. To make it plural, the -e changes to an -i, becoming i fiori (the flowers).

If fiore ends in -e, why do the adjectives rosso and bello end in -o?

Even though fiore belongs to the group of nouns that end in -e, it is still a masculine singular noun. Adjectives always change to match the gender and number of the noun they describe. Because rosso (red) and bello (beautiful) are regular adjectives, they use their standard -o ending for masculine singular words.

Why does the first è have an accent mark, but the second e doesn't?

The accent mark is used to tell two different words apart. è (with the accent) is the verb meaning "is", while e (without the accent) is the word for "and".

Will molto change its ending if we talk about multiple flowers?