I am trying to do html encode on the below string which has quotes , buts it not working

The server returns with quotes for the string

`string serverString= **“Test hello,”**` // this is returned from database

```
serverString =HttpUtility.HtmlEncode(serverString);

```

i am getting this result

```
�Test helloI,�

```

but still its not replacing and i am getting some diamond symbols on the asp.net page

Can anybody tell me what am i doing wrong.