forge (something) in fire

Translations
ковать (что-либо) в огне
Their friendship was forged in fire, having endured many hardships together.
Их дружба была выкована в огне, пройдя через множество трудностей вместе.
Definitions
To create, shape, or develop something through a process of intense difficulty, challenge, or testing, often implying that the end result is stronger or more resilient because it has endured hardship, similar to how metal is shaped and strengthened by being heated and hammered in fire.