ASP.Net Text with LineBreak from Multi-Line-TextBox to save in a database

I have PrivateMessage-System in my new Community-Page.

I have a Multiline-Textbox for the Text of a private message. I save this text in a string, this string in a ntext SQL-Coloumn. I read this text from the ntext SQL-Coloum in a string and show it in a label.

When I have 5 linebreaks with the "Enter"-Key in my Multi-line-textbox, the linebreaks will disappeared in the label.

I don't know where they gone lost and what I am doing wrong. any idea?