The depth of Rhysand's feelings for Feyre is honestly the most debated part of the series in my circles. I think his actions speak louder than his grand romantic gestures. The way he gives her space to grow into her own power, even when it terrifies him, is key. Under the Mountain, his cruelty was a performance to protect her from Amarantha's worse attentions – a brutal choice, but one made from a place of desperate calculation.
That said, the mating bond complicates everything. Is it genuine love or a supernatural compulsion? I lean toward it being both; the bond amplified what was already there, a respect and fascination that began in the first book. His "you are my salvation" speech gets quoted a lot, but for me, the quieter moments seal it. Like how he never forces her to stay in Velaris or demands she fits a certain mold. He loves the painter, the huntress, and the High Lady, all of them.
Sometimes I wonder if we forgive his manipulative streak too easily because he's charming. But in the end, his love seems rooted in seeing her as an equal, which is more than can be said for a lot of male leads in the genre.