Prevent the insertion of duplicate records

By using the stored procedure I can't able to insert the duplicate record but while inserting duplicate executing all the steps and it showing record inserted sucessfully but the duplicate record is not inserting in table even though am getting successful message but while inserting the duplicate record instead of executing all the steps,in front end I need to pass the  message like "record alredy eixts" ..Can any one tell me how to do like this?

Create a Stored procedure and Check before insert .
Here is sample Stored procedure

Create PROCEDURE [dbo].[USP_YOURINSERT]                                                
  (         
        @JOBTitle              VARCHAR(30)     = '',                           
        @RegID     VARCHAR(20)     = '',                              
        @RequirementID           VARCHAR(50)     = '',  
        @ReuiredExp           VARCHAR(50)     = '',  
        @JobLocation           VARCHAR(50)     = '',  
        @rowNum          INT =0
     )                                                          
AS                                                                  
BEGIN 
IF NOT EXISTS (SELECT * FROM YOURTABLENAME WHERE JOBTitle=@JOBTitle and RegID=@RegID)  
       BEGIN  
 
           INSERT INTO [YOURTABLENAME]     
                      (JOBTitle,RegID,RequirementID,ReuiredExp,JobLocation,rowNum)  
         VALUES  
                    (@JOBTitle,@RegID,@RequirementID,@ReuiredExp,@JobLocation,@rowNum)  
                   
                       GOTO S1_RTN  
        Select 'inserted'                 
        END  
        ELSE  
       BEGIN  
      Select 'JobTitle Exists'  
      END  
END

You can check my Article with similar Example.
http://www.c-sharpcorner.com/UploadFile/asmabegam/insert-select-update-delete-in-Asp-Net-with-simple-login/

before insert record  execute a query
select id from tbl where title=@title
if it returns record>0
then message 'record allready exists"
else
"insert record'