You don't show what model bike it is. If it's more than a couple of years old, the first place to look is the terminal on the starter where the cable connects. The rubber boot holds water from washing, rain, etc., and fosters corrosion on that terminal.
Last year my 95 M900 got to where sometimes it started without hesitation and sometimes acted like a dead battery. The connection at the starter was totally corroded. I upgraded the cables to 6 GA while I was replacing the bad connection and no problems since. Didn't even have to charge the battery.
I would be carefull jumping a bike from a car. If there is a ground in the system the car battery and alternator might supply more current than the bike can handle. (Happened to a friend of mine about 2 years ago, smoke everywhere, not a good sight)
If you have to jump it off a car, I'd take wwumonster's advice, do it with the car off.