To cost significa costar (= tener un precio).
No significa costar (= resultar difícil), que se traduce por to find it difficult.
EXAMPLES:
- The food cost me over thirty dollars. La comida me costó más de treinta dólares.
- The operation saved his life, but unfortunately it cost him a leg. La operación le salvó la vida, pero lamentablemente le costó una pierna.
- I've been told that even though it costs a lot of money, it's definitely worth it. Me han dicho que, aunque cuesta mucho dinero, sin duda vale la pena.