Is tough spelled tough?

Walk up to the toughest person, punch them in the face as hard as you can and noone will mess with you cus ur the new tough kid

When the going gets tuff the tuff gets going

Both phrasings can be used, but in different circumstances.(through is during the entire period of hardship)"We have survived through tough times."(in is some unspecified point within a period)"In...

No matter how tough times get, you have the potential to achieve the best of life.

He is indestructible to a lot of things, but he still has his limits.