You can do that with HTML code.
HTML Widget Option.
You can then configure each text node as a link using
<a> and assign it a title.
The code i used (taken as an example from here):
<a href=" " title="This is some text I want to display." style="background-color:#FFFFFF;color:#000000;text-decoration:none"> ID </a>:
<script> part was generated from me adding the field i wanted, and it's simply wrapped in a link tag.
Since these will be the field labels, you should turn the labels off.
This is the end result.
You can continue to style the labels with css so they would look better, but this is the basic version of what you asked.