What are the signs of a professional tenants?

[Jeff Howard]

We have just started renting our first house and, like anyone, we want to get good tenants.  We have had a few leads but they have all not qualified based on what they told us.  Too many dogs, did not want to pay that much rent, etc.  What I have noticed with many of them, they say things that i want to hear, for example.  "I clean houses for my current landlord and I am so glad your house does not smell like dogs"  or "We want to reduce the rent because we are going pay to have the grass cut."  Am I just being cynical?  I feel like I probably am.  Just curious how I can spot a professional tenant.