The brief
The Jetta had got hard to start, the crank taking longer than it should, and there was a strong petrol smell inside the cabin. He brought it in straight away, a petrol smell in the cabin isn't something to drive on. Those symptoms point at the fuel pump. The pump sits inside the tank and pushes petrol up to the engine at a set pressure, and when it weakens it can't build that pressure quickly on a cold start, which is the long crank, and it risks performance problems and engine damage as the supply gets inconsistent. The pump module is sealed into the top of the tank, and a tired seal there lets fuel vapour escape, which is the petrol smell in the cabin. A pump giving you that has run its course.
The diagnosis
A pressure test confirmed the in-tank pump wasn't holding rated pressure, and the pump module had a seep at its top seal, which was where the cabin smell was coming from. The fuel filter checked out clean, so it wasn't a restriction. That's a replacement. A weak fuel pump only gets weaker, and the next step is the no-start on the driveway, so it was getting changed now.
The work
System pressure was released, the access hatch over the tank reached, and the failed pump module drawn out. A new genuine VW-spec pump assembly went in with a fresh seal ring, the module locked down so the top sealed clean. Then the system was primed, the engine started, and the fuel pressure read on the gauge across idle and load to confirm it was holding spec, before the trim went back. A road test confirmed it started cleanly, idled steady, pulled away with the power back, and there was no petrol smell in the cabin.
The outcome
No petrol smell, a normal half-second crank, no hard starting, and full power under acceleration. The Jetta went home running cleanly and safely. A failing fuel pump gets steadily worse and then strands you with no warning, and a petrol smell in the cabin is never something to ignore, so acting on it meant a planned fix in the workshop rather than a tow.