Be-Sure-And-Be-Sure-To | Commonly Confused Words

Be sure and

/bi ˈʃʊr ənd/

Used to tell someone to do something with certainty or without fail

Be sure and lock the door before leaving.Be sure and bring your notebook to the meeting.Be sure and feed the cat while I'm away.

/bi ʃʊr tu/

To make certain or confirm that something is done

Be sure to check the lock before leaving.Be sure to bring an umbrella today.Be sure to call her before she leaves.

Be sure and is a more informal way of giving advice or instruction, often used in spoken English.
Be sure to is considered more formal and widely accepted in both spoken and written English.
Both expressions suggest ensuring that something is done, but be sure to is preferred in formal contexts.
Remember, be sure to uses the infinitive form ‘to’ which aligns with the standard grammatical structure.
In writing, especially in academic and professional contexts, be sure to is advisable to avoid informality.