I think it means Don't worry

It means "It's okay, or all right" when you want to the person don't worry about something.. However, you could to make a question for someone.. for example: "daijoubu?". In this context it means "are you okay?"

Hello Zeynep, The word you mean is "daijoubu". or 「だいじょうぶ」 and in Kanji・・・「大丈夫」 It means: OK Alright That's okay It's okay ...and so on. In it's most basic form it is equal to: " Okay, OK, or alright" ...in English. Like if someone bumps into you and says, "I'm sorry." And you say, "That's OK." In Japanese: Person: すみません。 You: 大丈夫です。 Hope that helps. Have fun using it！