problem with checkbox and arabic when insert to sql server

Question

i had a group of check boxes that insert the checked values in 1 row each time  by this code

SqlConnection sqlcon = new SqlConnection();

sqlcon.ConnectionString = @"Data Source=(local);Initial Catalog=cleopatra;Integrated Security=True";

List<string> checks = new List<string>();

foreach (Control cont in this.groupBox1.Controls)

{

if (cont is CheckBox)

{

if (((CheckBox)cont).Checked == true)

{

checks.Add(((CheckBox)cont).Text.ToString() + " , ");

}

}

}

sqlcon.Open();

SqlCommand sqlcmd = new SqlCommand("INSERT INTO pateint (mm) VALUES ( '" + string.Join(" ", checks) + "')", sqlcon);

sqlcmd.ExecuteNonQuery();

sqlcon.Close();

MessageBox.Show("ok");

and it insert as ???? marks i make it nchar and collation arabic