Is it correct to use "the sun don't shine" instead of "the sun doesn't shine"?
Thank you very much.
Strictly speaking, it's not correct. In Standard English, we should say 'doesn't'. However, it is used in some regional varieties. Certain phrases like that, or 'it don't pay the rent' are used, but they are collquial and would be marked wrong in an exam. There is an old song 'I don't care if the sun don't shine', and it sounds fine in that context, but in many contexts, it would just sound like an error. Go to parts of the States or the UK and you will hear it used, but it is a regionalism.