Well there's three versions of this story, mine, and yours and then the truth.
And we can put it down to circumstance our childhood then our youth.
Out of some sentimental gain I wanted you to feel my pain,
But it came back return to sender.

(Robbie Williams & Garry Barlow, Shame)

Bellatrix Lestrange

I hear you got married today. His name escapes my mind. Not that it's important. A Mudblood, Annie. Father says that that makes you no better. At least when you merely run away, you were still pure-blood. Still one of us.

How could you, An?

I hate you; I hate you so much that I want to scream; I do scream; I do cry and I do break things. You are the only one that ever saw me cry, and now, Goddamn you, I don't know what to do with myself. I do hate you; but most of all, I hate feeling this way about you, because you...I love you. I have been there your whole life, older than you, and yet you kept me safe; sane, trying to protect me like I was the most precious thing you had ever owned.

I tried to keep you from it all, this nonsense world where equality is seemingly more important than quality; keep you safe in our world, where I could always protect you like you did me. The one thing I could do for you, and you left. Run away, as though I disgusted you. As though you knew better. You always knew better.

I hate you. But I hate the fact that I love you more.

You should have stayed, Andromeda. Because now...now it's obvious that you never really loved us the way you said you did. Empty words. You...you were the only one I ever trusted. The only one who I thought saw all of me and loved me regardless. You didn't, did you? Otherwise you would still be here, and this mask that I used to hide behind wouldn't now be my constant companion. Who I have to be.

I have found someone now who has seen and continues to see all of me, and loves me regardless. He says my heart is pure, as pure as they come.

I don't tell Him that He is wrong; that Andromeda Black, a blood traitor, made me what I am. Made me love; and hate, all in the same breath, and without her I do not know where I would be, for better or worse. I do not tell Him, not because I would no longer be favoured, but because He would want rid of you, and as much as I am trying to wipe you from my mind, as if we had never fallen asleep curled into each other; as if we had never laid for hours talking nonsense, content with simply being; I cannot yet face the thought of a world without you. Without your pure heart. Even if it's now no longer Black.

Andromeda Tonks

I got married today. I know that you do not care; that by now the message is probably imprinted as deeply into your mind as the fact that you are a Black; the message that I am no longer your sister. No longer a part of your life.

I didn't want to leave you, Bella. My Bella. I would stay with you forever, if I could. But to stay in that house, to marry who they wanted me to, would have meant that a part of me would have died. The biggest part of me; the part of me that makes me who I am; makes me laugh, and love. Love you. I didn't...don't want a life without you in it, Bella. But not to leave would have been no life at all.

I know that now, with this...my marriage, you will see it as the ultimate betrayal. I never managed to convince you that the whole world doesn't revolve solely around you, did I? I sometimes think we all have a bit of Narcissa within us.

I know that, for you, it will never be enough not to be the centre of my world, and especially to live secondary to a muggle-born. I don't think I can yet come to terms with the fact that this, the happiest day of my life, is also the time when I realise that you - if not all of you, then a part; an important part - will hate me for the rest of our lives. That the 'us' we lived as for so long; The Black sisters, the Terrible twosome then, later, trio; will never be again. A small part of me hates you for this; hates your stubbornness, your blind belief in blood purity, your naive black-and-white-good-or-bad perspective. But I cannot bring myself to imagine not loving you.

Let me know what you think, constructive criticism always welcome :)

I may continue with a couple more letters between the two, but just a fledgling thought at this point...