Dear Haku,
I just wanted you to know that I love you so much, and miss you even more. I know I was never good to you, I treated you like trash but please forgive me, it was all I knew. If I had one chance to bring you back I would, for in my heart I know you loved me all along I was just to stubborn to believe it was true. Not a day goes bye that I don't think, what if, and why my life will never be the same again.
I miss you more and more, fighting that day with Kakashi and Naruto changed me they showed me what real companionship and friendship truly was. They showed me that you did love me and I loved you, but now you're gone and I'll never get to tell you my true feelings and for that I regret.
If I could have gone with you I would have, I miss you so much; please stay with me for ever.
With that Zabuza died of a broken heart, but now he could be with Haku in the other world and make-up for all the sins he had done to Haku.