Let’s go over how to stagger your Heart collection to get to the goal faster.
When sending characters on Heart earning tasks, make sure that the total adds up only to what is required for the level. Anything more will be lost. This is the normal mode of play.
But if you stagger the collection of Hearts, you can use characters from a previous round to add to the total for the next round.
As an example for a round requiring 8 Hearts, and you only have 3 characters, that would come out to 9 Hearts if you send them 3 times. Instead, on the last time send only 2 of them. After a suitable wait (let’s say 30 minutes or an hour), send the other 1. Once that round is completed, collect from the 2, and start the next round. When that character is done, collect the Heart and your next round will be 1 Heart ahead.
The numbers will depend on how many valid characters you have and that will determine the rate of progress that this will help with.
Note that the last round will not benefit from this technique, so just send all that you wish until you reach it’s goal.