Spanish phrase
No creo.
Meaning
I don't believe so.
When to use it
Expresses polite disagreement or doubt. It is used to gently reject or question a suggestion and is often followed by a brief reason.
Example dialogue
¿Deberíamos comprar esa camiseta?
Should we buy that T-shirt?
No creo, está muy cara.
I don't believe so, it's very expensive.