одну из своих

one of one's own

→ один
phrase Rare #28,648
one of one's own Used before or instead of a feminine noun meaning “one of one’s own [things].” The possessive refers back to the subject and changes in English according to context: “one of his own,” “one of her own,” or “one of your own.”
RU: Она показала мне одну из своих картин.
EN: She showed me one of her own paintings.

Том дал Мэри одну из своих гитар.

Tom gave Mary one of his guitars.