Do you mean after the pronoun? If so, then, those auxiliaries are used for emotive or contrastive emphasis when the speaker or writer feel strongly about something. Here are examples with do and does:
Ex: She thinks he doesn't love her, but he does love her.
Ex: You do look pretty in that new outfit! Quite stunning!
Ex: Are you all right? You do look a bit pale. Do please sit down.
Ex: I don't see very much of my old friends now, but I do still email them.
Ex: Was that a joke? I do believe you're teasing me!
When using auxiliaries for contrastive or emotive emphasis, the speaker gives them extra stress in pronunciation to make them sound louder, longer or higher in tone. When you see these words in print used in this way, they will normally be in italics or bold type or in CAPITAL LETTERS.
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