Qualifying Buyers

Does anyone have any approaches to qualifying buyers that works for them?  I usually send my buyers to lenders that I trust will do a good job of financially qualifying them.  But I find myself dealing with buyers that want to walk when things don't go as expected with an inspection.  They don't want to talk remediation with the sellers.  They just want to walk away.  I question their seriousness in actually purchasing after awhile.  Perfection doesn't exist.  I even find this with buyers represented by agents who submit offers on my listings.  I have had buyers walk away over minor items that can be easily fixed.  I begin to question whether they were serious to begin with.  How would you screen them before accepting their offer?