How do you spell the greek word tested faith?

There isn't a single Greek word that perfectly translates to "tested faith." Greek would use a phrase to convey that concept. The words you'd need would depend on the nuance you want to express:

* δοκιμαζομένη πίστις (dokimazoménē pístis): This is probably the closest single phrase. `δοκιμαζομένη` (dokimazoménē) means "being tested" or "being proven," and `πίστις` (pístis) means "faith." This emphasizes the *process* of faith being tested.

* πεπειραμένη πίστις (pepeiramenē pístis): Similar to the above, but `πεπειραμένη` (pepeiramenē) means "experienced" or "tried," implying the faith has *withstood* testing.

The best choice depends on the context. You would need to consider what aspect of "tested faith" you want to highlight: the act of testing, the endurance of the faith, the outcome of the test, etc.