I think believing blindly to a wrong person is more dangerous then going closer to a poisonous snake.Because if you believe anybody so much that he or she even know your weakness.Today or tomorrow he or she is going to take advantage of your weakness.And it is going to be very dangerous for you.
I am not telling you to stay away from people. Talk to people with a happy face,listen to them. But never show them your sadness or your weakness. because one day they are going to bite you on your weakness much more dangerously than a snake. And that day you can not take it and can not believe that the person you have believed so much can hurt you.But that day you have nothing to do because the person have all the weapons to let you down.
So, make people your strength by keeping a good relation with them, but never make them your weakness by telling your weakness to them.
Yes there must be some people who will never do anything wrong to you.But still be careful because human can change their nature so quickly.
For me being alone is much more better than being with wrong one.
Yes, you got your own understanding and knowledge on whatever people say, just have an option to decide and maybe be true to yourself not be able to covered by emotions and feelings,