WPF read Checkbox.Content

I have a couple of CheckBoxes with a TextBlock as content. Now I want to read out the TextBlock.Text from each Checkbox.

If I read out the content like checkBox.Content.ToString(); I only get System.Windows.Controls.TextBlock which kinda makes sense.

I also tried to create a new TextBlock and give it the content but it didn't work.

  TextBlock _tempTBL = new TextBlock();
  _tempTBL = checkBox.Content;

Any help is much appreciated.