How to whisper a large block of text to a player?

I attempted to whisper information regarding a player's character having been taken over by a doppleganger.  There was a couple of paragraphs of text and it was for the player's eyes only however only the first sentence was whispered and the rest was sent to open chat, ruining the secret.

Is there a way to do this?

Put the whispered text into a roll template. It is self-contained. Here is an example that should work in any game. Just make sure you select their token first:

/w "@{selected|character_name}" &{template:default}  {{=?{input text of whisper}}}

Another option would be to put it in a handout then just reveal it to the one player...

And whisper a link to the handout ? :D

You can also just wrap the paragraphed text in {{}} (they'll display as part of the whisper but keep the entire thing hidden).

/w "@{target|character_name}" {{Paragraph 1
Paragraph 2
Paragraph 3 etc etc}}