。
She really loves writing poetry.
Literal
She [topic-は] poems [object-を] write [nominalizer-こと] [subject-が] very is-fond-of.
Two grammar threads. First, こと nominalizes the verb phrase 詩を書く ('write poems') into a noun-like unit ('the writing of poems / writing poetry'). Second, the na-adjective 好き takes its object with が, not を — 詩を書くことが好き, not 詩を書くことを好き. This is one of the foundational quirks of Japanese: adjectives of preference (好き, 嫌い, 怖い, 上手, 下手) treat their object as a logical subject, marked with が. The polite ending です makes this slightly more refined than the casual 好きだ.