You can get Hearts Tickets from one of the following methods:
You will receive 20 free tickets at the start of the event. This is a one time credit.
In the Shop, you will have the Hearts Tickets entity, which will give you 70 free tickets every 4-hours. Once collected, the next set of 100 free tickets will be available for collection after the current 4-hour window expires.
In the shop, you have the Fortune Hearts event bundle. Purchase of this bundle will award you 70 free tickets. You will be awarded these free tickets only once in a 4-hour window. However, you can keep purchasing the pack as many times as you like. Only after the current 4-hour window expires, the next 70 free tickets will be awarded to you on your next purchase.
The mini game can also award you with more Tickets. You can use these tickets to play more mini games.