You need to BULK INSERT
using the CODEPAGE = 'ACP'
, which converts string data from Windows codepage 1252 to SQL Server codepage.
BULK INSERT dbo.temp FROM 'C:\Temp\file.csv'
WITH (FIELDTERMINATOR = ',', ROWTERMINATOR = '\n', CODEPAGE = 'ACP');
If you are bringing in UTF-8 data on a new enough version of SQL Server:
[...] , CODEPAGE = '65001');
You may also need to specify DATAFILETYPE = 'char|native|widechar|widenative'
.