Translation:The student is going to achieve what she wants.
"Lo" changes "que" from the subject of the dependent clause to the object.
To make that clearer--"que" without the accent is often "that" and it the subject of dependent clauses. "Lo que" is "what" and it is the direct object of dependent clauses. In this case, "ella quiere lo que".
I hope I didn't make things even more confusing.