To give home owners extra reassurance that you're not a member of the criminal fraternity, it's a good idea to commission a copy of your very own police check, or in other words, a statement from a government authority that proves your "lack of a criminal record". Having this available shows home owners that you're serious about presenting yourself as responsible and trustworthy and may put you ahead of the competition.
The process of commissioning a police check (known variously as a 'criminal record check' in Canada and a 'police certificate' in New Zealand) varies but is a fairly straightforward and inexpensive process. In Australia visit the Australian Federal Police website at www.afp.gov.au. In Canada look at the Royal Canadian Mounted Police website at www.rcmp-grc.gc.ca. In Germany try the Federal Office Justice at www.bundesjustizamt.de. In the UK, you can try the www.acro.police.uk or the www.gov.uk website. In the US, obtaining a criminal record check is less common, but you can try the travel.state.gov website which has some useful suggestions.
Your criminal record check should be current (preferably less than one year old).