Notes:

A little piece of fanart from pixiv celebrating Megaman 20th anniversary having Rock saving Roll from danger and depicting Roll being the the princess in distress.

This kind of reminds me of a mobile game called Tobe! Rockman or also Jump! Rockman in which you play as Rockman and the objective of the game is to save the princess which results to be Roll, xd. At the end of that game a heart appears between the two depicting Roll´s crush on Rock or possibly a shared love, lol:
http://megaman.wikia.com/wiki/Tobe!_Rockman
http://themechanicalmaniacs.com/articles/keitai.php

You may discover more about the game in the links above.