Caleb gave Aksah in marriage to Othniel, so she lived with Othniel in the city that he had captured in the Negev. The full meaning of this statement can be made explicit. Alternate translation: "Since you have given me in marriage to live in the Negev" (See: [[rc://en/ta/man/jit/figs-explicit]])
This implies that Caleb did give her the field when she asked him for it (verse 14). She is now asking for springs of water in addition to that field. (See: [[rc://en/ta/man/jit/figs-explicit]])