One of the problems you will have is the word "tame" (not to start the same debates from 5 years ago). When people say or hear "tame" they think of dogs, roll over, fetch, eat the treat out of my hand, sit and let me scratch you. With monitors it is more like taking a wild cat into your home, they can become people tolerant but not tame. Some cats will never let you pick them up without scratching you to shreds no matter how long you feed and house them. The same goes for your monitor.
It all will depend on your monitors personality and your personality. As was mentioned, it comes down to trust. If your monitor (and they are smart) knows it can scare you off so that it is left alone and that BIG hungry animal (that would be you) that wants to eat it leaves it alone, then it will scare you off everytime. Likewise if you force yourself on the monitor by insisting on handling it you will scare the animal more and stress it out (no more eating, no more thermoregulating, no more monitor).
Start small and let the monitor tell you its comfort level. Get it used to you reaching in to change the water dish. Keep the enclosure in an area where there is a decent level of human activity so the monitor can grow accustomed to the sounds and scents without it worrying about becoming a meal. Your monitor will let you know when AND IF you can progress beyond that point. Perhaps the best you could hope for is to not be charged whenever you change the water dish, and my friend, if that is the case, be happy with that.
Remember, anything beyond having a monitor living in your home is just a bonus
-Andrew