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"Sonríe" is a form of "sonreír", an intransitive verb which is often translated as "to smile". "Ser feliz" is an intransitive verb phrase which is often translated as "to be happy". Learn more about the difference between "sonríe" and "ser feliz" below.
sonreír()
An intransitive verb is one that does not require a direct object (e.g., The man sneezed.).
2. (to favor)
a. to smile on
Parece que la vida me sonríe: al fin he encontrado un trabajo donde me valoran de verdad.It seems that life smiles on me: I have finally found a job where I'm really valued.
sonreírse
A pronominal verb always uses a reflexive pronoun. (e.g., Te ves cansado.).
ser feliz()
An intransitive verb phrase is a phrase that combines a verb with a preposition or other particle and does not require a direct object (e.g., Everybody please stand up.).
a. to be happy
¿Eres feliz, mamá? - Anita, soy muy feliz porque has encontrado un muchacho bueno que te quiere.Are you happy, Mom? - I'm very happy because you've found a good boy who loves you, Anita.
