Ze gelooft in zichzelf. (She believes in herself.)
geloven takes "in" (geloven in = to believe in). Example: Ze gelooft in zichzelf. (She believes in herself.)
Ze gelooft in zichzelf. — She believes in herself. The preposition in is fixed, so it doesn't change with the sentence.
Fixed prepositions come up all over the A2 exam. The platform drills them in real exam tasks, AI-graded across all five DUO sections.