Selling my car to a nun

I posted yesterday about selling my 1998 Taurus and getting something else for it. Well a nun came by today to look at it and wants to buy it. I told her I'd give it to her for $3700 which is the asking price and she asked me to hold the car for her till tomorrow or Saturday when she could come by with a check for it.

She offered to give me a cashier's check for $1000 in the meantime as deposit money but I told her that she was a nun so her word was good enough for me.

Here are the questions.

Was I smart for doing this? I figured that if you can't trus a nun, who can you trust?

Should I accept a personal check from her for the car when she comes by? Again, I figure that she is a nun from the area, so she is probably the person least likely to give me a bad check.