Isn't it an interesting phenomenon how when something sad or painful happens in our life we begin to cry? Even more interesting is that once we begin to cry, salty water starts to come out of our eyes. Why does that happen? Why does salty water start to come out of our eyes?
So the explination is as follows...
The sad or painful situation that we experience seems to us as something bad. But really, we must believe, that even if it seems bad, it is really good - or at least there is something good hidden in it.
Now our eyes - the things that "perceive" what is happening to us may not always be telling us the full truth. That is why when we get sad and cry, Hashem makes the salty water pour out of our eyes. Salt and water are purifying and cleansing. Water cleans and salt is a natural dissinfectant (chlorine is actually an extract from salt).
So now we can put it all together. The eyes which falsley perceived the situation as bad are then flooded with salty water which is reminding us that maybe this is not so bad after all, but maybe this situation is really meant to cleanse and purify us.
Isn't it true that we usually feel better after a good cry, almost like we have been cleansed.
Rebbe Nachman teaches us that the more understanding we have (or emuna - that everything is really for our very best), the less we will experience the pain.
May Hashem bless us to see the good in every situation.