A First Officer reported they refused to operate an aircraft that had previously experienced a fuel leak but was signed off by maintenance to fly.

Narrative

The previous crew had a fuel imbalance of 1000lbs; attempted to crossfeed to correct; during the crossfeed the imbalance increased to 1400 lbs. They ended up shutting down the left engine after which the suspected fuel leak stopped and they diverted to ZZZ airport to a single engine landing. Maintenance could not duplicate and signed off the aircraft as 'found aircraft to be OK for continued service.'I believed this was too big of an issue to just randomly disappear and said that if we fly the aircraft it has to be under a legal ferry permit and with minimal crew to reduce risk. My Captain and the Chief Pilot disagreed and attempted to convince me that it's safe. Chief Pilot went as far as saying that as a First Officer I have no right to refuse the aircraft and only the Captain can do that; the Chief Pilot also offered to have someone else call me to explain why it's safe; I welcomed that option but no one called. Eventually I called dispatch and informed them that I have a safety concern with the aircraft and was taken off the flight. The aircraft flew passengers the next day after which a maintenance inspection in ZZZ1 airport found the fuel leak. Cause: My Captain spoke with maintenance and explained to me that they followed their checklist to verify the airworthiness of the aircraft. I believe that if the checklist doesn't lead to a solution then additional steps must be taken to solve the problem. Additionally; a culture of completing the mission regardless of safety concerns is not ideal for an operation that carries passengers.