Is Selling portfolio via seller financing a good idea?

[Julia Amelyan]

I'm selling my portfolio fo real estate and was offered seller financing for the full amount that I am asking for. The terms the buyer is giving me is 10 year term, 2.5% rate, and 12% down. What questions do I need to ask the buyer as not to scare him, but to verify that he has financials for this purchase and will actually make the payments for the years that we agree on. Also - should the downpayment be higher and rate be higher? Since this is a portfolio, the bank would most likely ask for 20-25% down and provide a higher rate? TIA