ترجمة - برتغالية برازيلية-يونانيّ - minha debilidade é minha fortaleza

Fortaleza is the fortress isn't it? The fortified position correct?

Fortaleza would be like force, it would be: 'my weakness is my force'. Thank you

But isn't force forteza? I get the meaning but shouldn't I use "fortres" metaphorically?