Spanish phrase
No estoy seguro.
Meaning
I'm not sure.
When to use it
Expresses lack of definite knowledge or certainty. Used in casual conversation when information is missing or when the speaker cannot confirm something.
Example dialogue
¿Cuánto cuesta este libro?
How much does this book cost?
No estoy seguro, pero creo que cuesta veinte euros.
I'm not sure, but I think it costs twenty euros.