Kokoro can also be pronounced "shin" (sheen) in Japanese.
In Chinese, it's xin.
Ki emerges from kokoro but kokoro is just the portal from non-existence and the roots of ki are in non-existence. Since our roots are in non-existence, we, in this world, can act from non-existence.
Kokoro is pronounced kokoro in Japanese. However I do see what you mean but think that's where things get a bit mixed up.
Xin is chinese and pronounced sheen in japanese.
Your thoughts on the matter come from chinese xin and that old chinese philosophy related to heart.
Anyway, your thoughts make sense from the path you are following so it's all good.