Why will we not get sick if we eat sodium chloride, even though chlorine is bad for us?

It depends on what you're talking about. Chlorine is an element, the element in it's raw form is toxic to humans, however sodium chloride is a molecule, and when the chlorine atoms bond with the sodium atoms, it chemically changes the properties of both. Chlorine in swimming pools isn't just the chlorine element, but rather a molecule known as Chloramine, which is NH2C, which, while still fatal in large enough doses, is mostly harmless in general. I can explain this all in further detail if you need me to.

it depends o n the ingreadients of it

Elements chemically combine to form compounds. The properties of a compound are totally different from those of the elements which form the compound.
Sodium and chlorine, both are individually elements. These two elements are toxic. But when these two combine, the new compound formed called sodium chloride shows totally different properties from those of sodium and chlorine.
Hence, sodium and chlorine are poisonous but sodium chloride is safe for us to consume.