When do you use buen, buena and bien? all terms mean “good”.
I am not a native Spanish speaker but I can help a little bit. Bien means ‘well’ rather than good, so it is the adverb, not the adjective. The difference between buen and bueno/a is not as clear to me, I will let a Spanish tutor answer 
Está bien (it is ok), “buena” is female, eg. una buena mujer,( a good wife) and “buen” the contrary, ; un buen libro (a good book) , and now we say; “la mujer es buena” and “el libro es bueno” , ¿los has entendido bien? (you got it?), un abrazo,
2 Likes
Thanks for the explanation. =) Got the "bien’ part
Thanks for your reply. I’m not sure if I understood this right. Bien is an adverb so it describes a verb. Buen, buena/bueno are adjectives. Based on your example for sentences describing libro, does it follow that buen is used before a noun and buena/bueno after a noun?
you got it, “bueno/a” is an adjective. Only the “o” disappears when it is placed BEFORE the noun, “un buen libro” “un buen hombre” but with the “o” when placed after it; un libro bueno. This does not happen with the female word “buena”; una buena mujer and “una mujer buena”. Bien is an adverb and has no conjugation; example; está bien (he is ok), están bien (they are ok), so don’t write; están bienes. regards Ed
1 Like
Buena pregunta? Espero responder bien. Primero: Buen y buena es lo mismo. Buen, masculino; Buena, femenino. Vale?. Segundo: Buen vs Bien. Buen o buena son adjetivos. Bien no es un adjetivo, es adverbio. Si en la frase hay un nombre, tienes que utilizar buen. Si en la frase hay un verbo, tienes que utilizar bien.