Do you think Regina will keep Marion's heart safe and sound in the box until they find a cure?

I'm kinda apprehensive about whether or not Regina is gonna be keeping her word on helping find a cure for Marion and keep the heart safe in the box. I'm realizing she has the opportunity to crush it without anyone knowing so Marion will be dead and she and Robin can be together without him knowing she did it. I'm hoping she plans to give the heart to Henry to protect it or the Charmings or something or maybe Robin. As much as I want her and Robin to be together and/or for Regina to be happy, crushing Marion's heart is gonna ruin a lot of Regina's hard work of being a hero. She already has thunk twice about going back in time and killing Marion. Course I'm worried about her intentions on finding the writer of the storybook will be. Even though Henry will be helping her, is he gonna like what she's gonna do when they do find the writer?