Error: pandas hashtable keyerror

I think first is best investigate, what are real columns names, if convert to list better are seen some whitespaces or similar:

print (reviews_new.columns.tolist())

---

I think there can be 2 problems (obviously):

1.whitespaces in columns names (maybe in data also)

Solutions are strip whitespaces in column names:

reviews_new.columns = reviews_new.columns.str.strip()

Or add parameter skipinitialspace to read_csv:

reviews_new = pd.read_csv("D:\\aviva.csv", skipinitialspace=True)

2.different separator as default ,

Solution is add parameter sep:

#sep is ;
reviews_new = pd.read_csv("D:\\aviva.csv", sep=';')
#sep is whitespace
reviews_new = pd.read_csv("D:\\aviva.csv", sep='\s+')
reviews_new = pd.read_csv("D:\\aviva.csv", delim_whitespace=True)

EDIT:

You get whitespace in column name, so need 1.solutions:

print (reviews_new.columns.tolist())
['Name', ' Date', ' review'] 
          ^        ^