Do you ever really know a person?

Recently I have been hooked on the investigation discovery station.  I don't know if you are familiar with this station but basically it's re-inactments of true murder mysteries, cold cases, strange disapperances , kidnappings, and so forth.  For some reason I love it and can't get enough of it.  However there is one series that I just can't get myself to watch.  It's called  "The devil you know".  It has real life stories of people that have been masquerading as "normal, law abiding citizens", but in reality have a deep dark secret, such as serial killers, rapists, kidnappers, pedophiles, etc.  The big catch phrase they use in the commercial is "Do you really know your neighbor?"   This series freaks me out, but it has got me thinking.  Do we really know our neighbors and how much can or should we trust them?  I love my neighbors, I do trust them, we play together, have b-bq's, watch each others kids and so on.  Recently somethings have shaken me up a bit and rattled my faith in trusting people outside of my family.  I hate that the world is a sick place and that I can't trust people or places.  I hate that I have to really contemplate letting my kids go somewhere because I am worried about some sicko taking them or hurting them.  Honestly what has this world come to?  I just want to board up my house and never leave.  But then I am reminded of something my mom told me once when I was younger.  I once asked her how she was able to let us go places, and do things without worrying.  This is what she told me.  She said, I always worry, but I pray each day that you will be safe, and that you will make good choices.  I put my faith in the Lord, and that's all I can do.  I guess that really is all we can do.  I take precaution so that my children are safe in my home, the only precaution I can take when they are outside of my home, besides teaching them, is to have faith in the Lord.  It's hard.  But honestly, I can't keep them in my home all the time.  I need to have more faith and put my trust in the Lord.  It's like driving a car, I can make sure I obey all the laws, drive safe and cautiously, and be aware of other drivers on the road, but I can't do anything about the other drivers or the decisions they make while behind the wheel.  All I can do is have faith, and put my trust in the Lord to keep me safe. 
I know this might seem random and incoherent.  I apologize for my ramblings.  Like I said somethings have just shaken me up a bit and I needed to rant for a moment.  Thanks!