Try this:
DateTime d = new DateTime(2017, 6, 7, 13, 14, 15, DateTimeKind.Utc);
string s = d.ToLocalTime().ToString("yyyy-MM-dd HH:mm:sszzz");
Console.WriteLine(s);
It produces this:
2017-06-07 14:14:15+01:00
because I'm on UK time - currently BST, one hour ahead of UTC.