There can be no greater gift given to a Necromancer than a soul fragment. Hariel as a true-born Necromancer figures Tom Riddle must have been courting her since the moment of her birth considering when he gave his to her. She naturally accepts his offer; it's a Horcrux for goodness sake. But she can't quite understand why Tom keeps trying to run from her after she does.

Attempting to create a new mode of magical travel Heather accidentally ends up in an alternate reality. With no way home she gets comfy, or would if the goblins didn't decide to dump her alternate self on her, and warn her that the man she trusted with her life was trying to kill her new charge. Or in which Heather becomes a world-traveling savior because she hates the floo.

Finding your soulmate is the only true way to gain immortality. Tom, since childhood, has sought far and wide for his other half, the key to his eternity, and finds her sitting in Muggle London. He is a catch, so no sane individual, let alone his soulmate, would deny bonding with him for shared immortality. Which is why he's put off when she says 'no' to his offer of courtship.

Arthur tells Harry and George the story of the first time Arthur was allowed to bathe the newborn Fred and George. It didn't go well.

The first time is impossible and yet she does it anyway. The second time is as easy as breathing and it helps her to understand that her impossible choice was the only one she could have ever taken.