。
Can she endure a long journey?
Literal
She [topic-は] long-trip [to-に] can-endure [question-か]?
耐えられるか uses the potential form of 耐える ('to endure') — 'can she endure?' The question marker か makes it a direct question. 長旅 ('long trip') is a compound noun: 長 (long) + 旅 (trip). The sentence expresses concern about someone's physical or mental capacity for an extended journey.