If I break my hip, will I have to have my hip replaced?

No. Many hip fractures can be fixed with screws or nails. About 20% require some form of replacement.
No. If the fracture occurs close to the head, through the femoral "neck", and it is displaced, then it may require either a total hip replacement or a "partial" hip replacement. If the fracture is more distal to the hip, then usually open reduction and internal fixation is done. Occasionally (in 10%) people develop arthritis or "avascular necrosis" later on and need a hip replacement for that.