。
She tried to kill herself.
Literal
She [topic-は] suicide [object-を] do-let's [quotative-と] did.
The construction 自殺をしようとした uses 自殺 as a noun with explicit を, then verbalizes with する. An alternative form drops the を and treats 自殺 as a suru-verb stem directly (自殺しようとした). Both forms coexist for nouns that pair with する — お茶をする / お茶する, 勉強する / 勉強をする — and the choice usually doesn't change the meaning, though the version with を can feel slightly more deliberate or formal. The volitional + とする pattern frames the act as an attempt that didn't reach completion.