I - Mein sure - vishwaas/ yakeen About - Baare mein it - iske. So I'm sure about it means "mujhe iske baare mein poora yakeen/ vishwaas hai" you - tum & here sure also indicating some certainity so its better to include poora or pakka. "are you sure?" means "kya tumhe poora/ pakka yakeen hai?"

Some Additional Examples of "Mujhey (Poora) Yakeen Hai" - Mujhey (Poora) Vishwaas Hai - I am sure - Lit Meaning - I do believe - Yakeen is more on the Urdu Side a Vishwaas on Hindi side But Both are used in Colloquial Langauge *** Eg. Mujhey Poora Yakeen hai Ki... I am absolutely sure that .... Mujhey Vishwaas Tha ki ... I was sure that.... Conversation: Person A - Kya tumhe poora yakeen hai ki jo tum kar rahe ho...wo sahi hai? - Are you sure that what you are doing is right? Person B - Haan! Mujhey Poora Yakeen Hai - Yes! I am sure. A little contribution to this already correct answer :)

Well This is not really realted to the Language and Grammer... But The very phrase "I am sure..." reminds me of a real story that took place near Christmas and a Doctor and a 7 year old child. The name of the Doctor was John M. Briley Jr. The patient was suffering from a kidney malfunction. All efforts being failed the doctor felt guilty for failing the child. He tried to to do something different not knowing if it would work or not. A drug that takes half an hour if it is to work...if not...then... Before giving the child the drug this is the conversation that took place between them... Doctor: Do you pray? Child: Yes every night...But I don't think He listens to me. Doctor: I am sure He does. The doctor said not sure himself but still he wanted to cheer him up. His face was bloated and dark as water filled his body The Drug was given and nurse was told to see what after half an hour. After two 2 minutes the nurse came running. The floodgates have opened...he is urinating like HELL! The doctor rushed...the child could finally urinate...and smiled after weeks ... The doctor was just amazed.... He says "was is sheer pharmalogy breaking the rules or.... as the carol played on the radio....and he heard these lines in it ...May be I didn't do such a wonderful thing after all :)

Mr. Dev said it Right and Yes Mujhey Maloom hai = I know Maloom is more on the Urdu side. It's a part of the colloquial Hindi Remimds me of the dialogue from RNBJ - O! Ji mujhey maloom hai ji jitni bakwaas baatein main karta hoon...ussey kai zayada bakwaas dancing main karta hoon ji (I know my dancing is even more rubbish than my talks) http://www.youtube.com/watch?v=R2uCjHjFHB0

Dev is right, sorry Amey. Malum means to know. To answer Annily's question: "you sure" is usually "pakka?" (pronounced puck-ah) it means "sure?"