What is the ruling on the non-refundable deposit stipulated by a matchmaker in exchange for searching for a wife, whether one is found or not?

The work of a matchmaker in seeking a wife is considered a "ju'alah contract" (contract for a specified outcome) and not an "ijarah contract" (lease or hire contract), because it is based on achieving a specific result. Ignorance of the work's exact nature and duration is excused in this type of contract. The matchmaker is not entitled to any payment unless she fully completes the task and achieves the desired outcome. She is not permitted to stipulate a non-refundable deposit. If she does not find the requested wife, she is not entitled to anything.