“坚强的”用英语怎么说？

我当时不知道罗恩有那么坚强的个性。I didn't know Ron had that much strength of character.他们面对困难表现了坚强的毅力。They showed great perseverance in the face of difficulty.她具有坚强的意志和速决的才能.She had a strong will and power of rapid decision....