The polite way to ask for something in Mandarin Chinese is to preface your request with máfan nǐ. This translates as “May I trouble you to….”

Máfan 麻煩 has two characters and nǐ 你 is a single character meaning “you.” Both characters of máfan have the meaning of “to bother,” and together they mean “trouble” or “troublesome.”
Examples of Máfan Nǐ
 
    Máfan nǐ gěi wǒ yī bēi kāishuǐ.
    麻煩你給我一杯開水｡
    麻烦你给我一杯开水｡
    May I trouble you to give me a glass of water.

    Máfan nǐ gàosu tā wǒ mǎshàng lái.
    麻煩你告訴他我馬上來｡
    麻烦你告诉他我马上来｡
    May I trouble you to tell him I’m coming immediately.