Nǐ dǒnɡ wǒde yìsi mɑ?
你懂我的意思吗?
You know what I'm saying?
Notes:
你(nǐ): you
懂(dǒnɡ): understand
我的(wǒde): my
意思(yìsi): meaning
吗(mɑ): question word
Example:
A:你懂我的意思吗?
Nǐ dǒnɡ wǒde yìsi mɑ?
You know what I'm saying?
B:说实话,我不懂。
Shuōshíhuà,wǒ bùdǒnɡ.
To be honest, I don't understand.