。
She'll probably become a teacher.
Literal
She [topic-は] teacher become-probably.
A clean trio: noun-に + なる (the standard 'become X' construction) followed by だろう for probability. 教師になる ('become a teacher') is one of the canonical examples of this construction in textbooks because it neatly shows the に-marker on the role being moved into. だろう then frames the becoming as a guess about the future rather than a settled fact.