When we want to reinforce an idea expressed in a sentence, there are plenty of adverbs we can use, from which the most commonly used is REALLY.
This is good. This is REALLY good.
However, English also offers us the possibility of using the auxiliary verbs DO, DOES and DID to emphasize a thought. They must be used only when the sentences are in the present and past tenses.
I cook all kinds of dishes. I DO cook all kinds of dishes.
She has brilliant ideas. She DOES have brilliant ideas.
They gave it their best shot. They DID give it their best shot.
It is very important that you observe you must keep the verb in the base form when using the emphatic DO / DOES / DID.