''Seller won't tell how much he has left on mortgage''

[Connelle Dewberry]

I've been eyeing a property for a long time, wasn't able to reach the owner until today. He just happen at the house as I rode by. He had already been approached by many other investors, but said he liked my approach because I didn't treat him as being destitude or broke needing to sell. Long story short, he was very receptive of me, gave me a tour of the property and everything I needed except how  much was left on the mortgage to pay. He said he thought that was personal and didn't feel comfortable giving me that information. I told him I would need know all the numbers to make him the best offer possible. What do 

you do, and how can you make an accurate offer on property without knowing? Thanks!