Chemical reactions in an evolved portion of the anatomy makes up the mind and will. Emotions are primarily the result of lower portions of the mind (and even the body, and just genetic code) manipulating higher portions of the mind. The genes want to perpetuate, the body has a whole section devoted entirely to genetic immortality, the lower mind makes us fall in love so that we can acquire a breeding partner.
It’s all pretty straight forward stuff actually. Pretty well explained these days backed up by experimentation, and manipulable through drugs (both with and without supervision). Religions were designed by pre-scientific people to explain things they didn’t understand. But a lot of that stuff is very understandable now. There are identifiable chemical reactions to these things now, we can look at a brain scan and say “this guy is happy, this one is depressed, this one is in the early infatuation stage of love, this one is in the long haul comfortable partner stage”. It ain’t tough, and it ain’t mystical.
Oh, what a happy accident.