His anger and frustration

You don't want him to hate you--it'd make for a really awkward relationship in battle. You do know, however, you've caused him suffering the past fifty years by closing yourself off to him and that he must have some deep resentment for it. You never even noticed your facial expression changed, but there's no use hiding it now.

"Are you angry with me, Senbonzakura?" You ask steadily, never wavering, never breaking the contact you have with the tree.

"I'm not prone to anger, Byakuya-sama," he replies, just as steady and emotionless as you asked.

"A lie."

The mood seems to dampen, but you're not ready to give up yet. You know that he's easy to anger, to set off and you're determined, for some reason, to get it out of him. One of your hands moves up the surface of the tree, ignoring the painful scratches in your sensitive palm. If only you could see that anger and displeasure with you, you'll know that something in the world will punish you instead of praising your efforts. Even though you've made amends since then, you demeaned him for your own purposes, forgot, at times, that he was more than a tool of battle and you don't want him to forgive you so easily... but why?

"You will do anything I ask, is that right, Senbonzakura?"

He seems to hesitate, you can feel it beneath your scratched palms. "Yes. I will do as you ask. What is it you want from me?"

"I only wish for your honesty. If you have anything closely resembling resent, then you must show me how strongly I have wounded you. You know words do not persuade me."