By hitman I'm assuming you mean a hired killer. There are no formal qualifications for this trade so you can simply say "I am a hitman", have your letterhead and business cards printed with that and nobody can say you're not.

However, there are some issues that immediately spring to mind. In most - if not all - religions, cultures and countries, killing is seen as wrong unless specifically condoned by the ruling government, monarch or dictator. This makes it very difficult to advertise your profession.

One can only assume that hitmen (using that term to embrace the women in the profession too), despite their lack of official qualifications, are actually suitably proficient at killing. In this business reputation is gained by word of mouth and so if you miss your target you will soon be out of work - and feel a little guilty about the number of trees that were felled to print your letterhead and business cards with the now defunct title "hitman" on them.

Despite the glamour surrounding hitmen in films, it's a lonely game, you can't arrive home after a hard day's work and tell your loving partner about the silly mistake you made while garotting this president or the accuracy with which your rifle bullet took out that potentate - if you did, you would be duty bound to kill your partner too, which would really spoil your day. No, you'd have to keep quiet about it so nobody could appreciate your awesome skills.

And how much to charge? This is not a 9-5 job, so despite being the fashionable hitman one month you may be waiting for weeks for your an assignment the next, so you'd need to think about surviving 'between jobs', it does put the price up.

You would be so hated by so many people and countries, it would be a real nightmare getting travel visas - you really don't want these people to find out who you really are.

Finally, 'money laundering', it's political correctness gone mad, but you try dropping into your local bank with 50k to deposit they will start asking all sorts of difficult questions - you will probably end up with it tucked under your mattress and that's a real worry when you're out of the country on a 'city break' (if you get my drift) in some far-flung land. And don't get me started on pension arrangements...