Amazing in Spanish is translated as "increíble" or "asombroso".
asombroso
asombroso/a
asombroso xox
Te amo, Austin.
Tú eres asombroso y deseo que te fuera mío.
Maravilloso, pasmoso, admirable, prodigioso, asombroso, estupendo
Creo que usted es/tu eres estupendo/a (formal/informal; male/female)
You're amazing = Tu eres/usted es asombroso/a (informal/formal; male/female) Your amazing (intelligence) = Tu/su (inteligencia) pasmosa (informal/formal)
Yo pienso que eres hermoso/a. (male/female) Hope this helps. Xx
El asombroso mundo de Borjamari y Pocholo - 2004 is rated/received certificates of: Argentina:13
(Literally) Se le cayo la mandibula (Not sure whether it has the same metaphorical meaning in Spanish) (If not, you could perhaps say: Fue asombrado - He was astonished)