Mikazuki no kokoro
Kuresentu is what I have in mind.
my heart
heart is kokoro
私の心の中is the way to say 'in my heart' in the Japanese language. hope i have helped! :)
kuroikokoro
kuraikokoro
meinu
You may say 'kokoro kara,' which literally (and conveniently) means "from the heart."
mikkatsuki
Mikazuki
To refer to the shape, you may say 'mikadzukikeino,' written: 三日月形の
心魂 Shinkon