Despite many challenges, his steadfastness helped him achieve his dream in the end.

steadfastness 是由形容词 steadfast（坚定的、不动摇的）加上名词后缀 -ness 构成的名词。stead 来自古英语，表示"固定的位置"，fast 表示"牢固的、不动的"，合起来表示"坚定不移的"。steadfastness 指"坚定不移的品质或状态"，即"坚定、坚毅"。