Heart in a box2015
by Kelly Thompson
"When the Man with No Name breaks Emma's heart, she wants to die. But you never die from these things; you just want to. In a moment of weakness, she wishes her broken heart away and a mysterious stranger--who may or may not be totally evil--obliges. But emptiness is even worse than grief, and Emma sets out to collect the seven pieces of her heart spread across the country, a journey that forces her to face her own history and the cost of recapturing it, and leads inevitably to a confrontation with the Man with No Name himself!"--
— from OpenLibrary
2 editions at OpenLibrary