Pero vs sino
Is there any rule about which form of "but" to use and when? I can't figure out any pattern.
I will give you some examples
Me gustaria ayudarte pero no puedo-I would like to help you but I can't El vestido no era ❤❤❤❤❤ sino gris-The dress was not black but rather gray.
Queria ir al cine pero no pude-I wanted to go to the movies but I couldn't No es que no me guste la pelicula sino que no la entiendo. It's not that I don't like the film but I don't understand it.
They are not interchangeable. Sino is used almost always to contradict what has already been stated.
I hope this helps.
Sino is an elegant way to provide a non-obvious alternative to a negative statement, without having to start a new sentence.
To avoid confusing it with pero, try replacing it with although–if it works, it's pero; otherwise, it's sino.
> — Me apetecía verte hoy, pero hasta mañana no puedo.
> "I felt like seeing you today, (but/although) until tomorrow, I can't."
> — Pues yo no contaba con verte hoy, sino mañana, así que perfecto.
> "(Well) I wasn't counting on seeing you today, (but/I was counting on seeing you) tomorrow, so that's perfect."
I go deep into the usage context of sino in this NachoTime post.