。
She'll probably do her best to get here on time.
Literal
She [topic-は] on-time here [to-へ] come [so that-ように] all-effort [object-を] exhaust [probably-でしょう].
Several patterns layer here: ~ように ('so that / in order to') marks the goal of arriving on time, 全力を尽くす ('to exhaust all effort / do one's utmost') is an emphatic set phrase, and ~でしょう adds the speaker's conjecture ('probably will'). 定刻に ('on time / at the scheduled time') is more formal than 時間通りに.