Vlook up help

So hopefully I will explain this right and I have attached a print screen also
Sheet one has columns A, B, C
Sheet two has C and D

I want to match these two by the first few letters in B - which will be different in every cell going down (from sheet 1) and D (from sheet 2)

And to display the results in sheet 2 so that I can also see C

Some of them may not match. Whatever I am doing my formula is not working. Any help from anyone would be VERY much appreciated.