Word that I kept hearing at the end of a sentence
The "word" you are asking about is not one word but two: "对不对" 
对： Right
不对： Wrong
So he is asking you that: Is it correct or not? But actually meaning for this is trying to convince people like "Don't you think what i said is very reasonable? Yes, I am right!"

The Pinyin for these words: DUI 对, BU 不， DUI 对