you were very close to Ukitake, but you weren't connected in any way like a relationship.. but that's exactly what it was all heading towards. He asked to transfer you from the 4th division to his division under the pretext of a dangerous mission. You were very happy about it, because now you could be closer to him and help him if his illness worsened.

the Shinigami didn't like you because they thought that you would become a lieutenant not because of your abilities, but because of your closeness to their captain.