I don't know
translate please.....I don't know
No sé = I don't know (as in, I don't have that information)
No conozco = I don't know (as in, I'm not aquainted-with a person or location). This is from the verb conocer. No conozco al Señor Gómez. or No conozco la Ciudad de México.
no sé= I don't know'
As added information this is from the verb saber- to know. Click on the conjugator above and enter the verb. It will break it down into all its positive tenses. To form the negative, simply place "no" before the verb.