своему учителю

to one's teacher

→ свой
phrase Uncommon #23,254
to one's teacher Dative form after verbs like trust, write to, bow to. Refers to the speaker's or subject's own teacher.
RU: Я подарил цветы своему учителю.
EN: I gave flowers to my teacher.

Нужно доверять своему учителю.

You need to trust your teacher.

— Четыреста ударов (1959)

Не стесняйся задавать своему учителю вопрос.

Don't hesitate to ask your teacher a question.