I know that both 'estar ansioso de' and 'estar ansioso por' mean to be excited for something or looking forward to it, but how do I decide which one to use? Do the two have slightly different meanings? Are any other preposition ever used instead of 'de' and 'por' in this context?
According to RAE, they can both be used interchangeably, but:
- if what follows is a noun, normally de is used
- if what follows is a sentence, any of them can be used
Both "de" and "por" can be used. I'm not sure if both of them are gramatically correct, but they are used in regular spanish.
Particularly, I think "por" sounds better (and it's also more used in Peru). It kinda answers the implicit question ¿por qué estás ansioso?:
¿Por qué estás ansioso? (Why are you anxious?)
Estoy ansioso por mi examen de manejo. (I'm anxious about my driving test.)
Sounds better than "Estoy ansioso de mi examen ...", right?
Estar ansioso de and estar ansioso por can be similar insofar as they mean "to be anxious regarding..."
But they could have different versions of "regarding." "Estar ansioso por ti" means "to be afraid FOR you" (that something bad will happen to you).
"Estar ansioso de ti" could mean to be afraid OF you (that you will do something bad to me).