"Knights of the Old Republic" is a role-playing video game by developers Bioware and Lucas Arts. It is for play on the Xbox home console, as well as on PC and Mac computer formats. It takes place in the enormous Star Wars universe and spans many worlds throughout the game. A pivotal point of the later part of the game is entering the Sith base. One of the ways in which you can do so is to interrogate the Sith spy being held within the Republic embassy. Successfully interrogating him will provide you with a passcode to enter the Sith base.
Boost up your Persuasion skills prior to attempting the interrogation. When levelling up in battle, you receive points that you may assign to the various skills of your character. Assign your points to "Charisma." Boosting Charisma to above 75 should suffice.
Begin the interrogation of the Sith prisoner. Head to the Republic embassy on the planet Manaan. Speak to the man at the front desk in the embassy to get access to the Sith spy being held.
Use your Persuasion options to interrogate him. When the interrogation begins, you will be presented with a set of responses to select between for each question. Select the responses that have "(Persuade)" at the end. These will be referencing his fiancé, Tela.
Avoid threatening the spy or asking about his companion. You will have a couple of instances when there is not a "(Persuade)" at the end of any of the questions. These points are meant to throw you off from accomplishing the interrogation, by threatening or asking about the other man.
Try again if the prisoner stops talking. If you ask him the wrong series of questions, the prisoner will freeze up, which means that you will have to try again. There is no penalty to attempting multiple times.