Transact SQL :: How To Query International Characters

i've worked with SQL Databases for years now, but never needed to deal with international characters.  I am trying to search strings like surname in a column that might have international letters/characters, such as:

select * from [dbo].[User] where LastName like '%HekimoÄŸlu%'

It doesn't retrieves anything.  I've googled for while in a hope to find some solution quickly, but to my surprise I couldn't. how to query string columns that include international characters such as above.I am using SQL Server 2012, Nvarchar(100) for column.