According to Toast content schema Text elements:
Since the Windows 10 Anniversary Update, you can control how many lines of text are displayed by using the HintMaxLines property on the text. The default (and maximum) is up to 2 lines of text for the title, and up to 4 lines (combined) for the two additional description elements (the second and third AdaptiveText).
And AppNotificationBuilder.AddText Method:
A maximum of three text elements can be added to an app notification.
And according to my test, the notification UI shows characters ending with a \n
as a text element.
So, your desired notification needs five text elements actually while A maximum of three text elements can be added to an app notification.