Your agent has a fiduciary duty to always look out for your best interest. Its can of hard to say whether they're acting in your best interest if they want to rent it later on. However, it may be a win win. You have to treat him like any other tenant you want renting your property. You need to see credit scores ahead of time, paystubs, W-2's and see if they can even really afford to rent the home and find out what their current rental history is for the last 2 years.
I think once you see him as a possible tenant vs your realtor things will start to clear up a lot more. If the answers come back shaky then its best he stay your Realtor and not your tenant.
Remember, a lot of people are downsizing, they got in way over their heads during the boom and he/she may have been one of them. It doesn't necessarily mean ditch them unless you are seriously uncomfortable. You have to have some level of trust with your Realtor.
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