And, thanks to your love, there lives darkly in meThe quickening aroma that rose from the soil (7-8)
Neruda compares the feelings his lover inspires in him to an "aroma," a smell. It sounds weird at first, but once you start to imagine how a smell affects you, it makes more sense. A smell can be so powerful that you feel like it's inside of you. It travels through the air and into your body in a way that a sight cannot. This is what love is like, infectious to the core.