If all you want to do is get the value from the second column in the ListView, and write it to the RichTextBox:
private string space = " ";
private string newLineString = Environment.NewLine;
private void WriteLvToRtfBox_Click(object sender, EventArgs e)
{
foreach (ListViewItem lvItem in listView1.Items)
{
richTextBox1.Text +=
lvItem.SubItems[1]
.Text
.Replace(newLineString, String.Empty)
.Replace(space, String.Empty)
+ newLineString;
}
}