Moody VW Jetta 2000 that has a temper

I have a VW which I love, but about two to three years ago it started having an issue… sometimes it just doesn’t want to start. When you turn the ignition it will crank and crank, but will not attempt to catch. There is no frequency, and only does it sporadically. Sometimes its once a month, sometimes its once a week, cold or hot, full or low tank. I took it to several garages where they were puzzled. When it does start (most of the time) it starts right up, no trouble at all.



My wife is tired of this car and its temper, because sometimes it has left us sit for up to 20 min before it finally starts (normally just 2-3 mins).



Any Ideas?