Yes, Feyre is beautiful
I’ve seen several comments recently from users arguing that Feyre is plain or just average looking. I think this stems from fans not reading closely enough, and fundamentally misunderstanding Feyre’s character and taking Feyre's negative self-thoughts at face value. In ACOTAR and the first half of ACOMAF, Feyre’s low self-esteem and lack of confidence is extremely evident. In fact, it is a core part of her early characterization. She has internalized a lot of negativity from her family, as well as her life circumstances, and that has led to deep insecurities about her self-worth, talents, place in the world, and her own looks. She doesn’t see her own beauty because she doesn’t see anything positive about herself. And some readers just take her at her word.
But let's look at the actual text evidence. Even despite Feyre's deeply negative view of herself, in chapter 7 of ACOTAR, she admits:
>I would have lived up to my namesake were it not for the effects of poverty, but I'd never particularly cared. Beauty didn't mean anything in the forest.
Feyre means “fair” or “beautiful.” So from her acknowledgement, we can assume that when her face is filled out and she is no longer in and out of starvation, she is beautiful.
This interaction in Chapter 22 of ACOTAR, between Feyre and Tamlin, shows us the discrepancy between how Feyre sees herself and how others see her.
>Tamlin gave me a lazy grin. "And miss a chance to show off to a beautiful woman? Never." I smiled down at my plate. “You do look beautiful," he said quietly. "I mean it," he added when my mouth twisted to the side." Didn't you look in the mirror?" Though his bruise still marred my neck, I had looked pretty. Feminine. I wouldn't go so far as to call myself a beauty, but ...
Even cheeky, teasing, sarcastic Lucien sees her beauty:
>"Cauldron boil me," Lucien whistled as I came down the stairs. "She looks positively Fae." (ACOTAR, chapter 25)
And we don’t see that disbelief of her own beauty begin to change until the middle of ACOMAF (Chapter 42) as she gains self-confidence, and develops healthy, positive relationships with people who care for her.
>I waited for the blush, the shyness, to creep in.
But I was beautiful. I was strong.
I had survived-triumphed.
And just for good measure, let’s cite some evidence from other characters. When Bryce first meets Feyre in chapter 78 of HOSAB, she describes her in this way:
>First, a lovely female with the same brown-gold hair as the one already standing before Bryce entered.
Interestingly, Bryce assigns no adjective of beauty to Amren when she introduces her, so it isn't as if she describes everyone this way.
In Chapter 57 of ACOSF, Cassian says:
>Feyre might as well have been a goddess of old, crowned and glowing, her belly swollen with life. Her serene face was lovely, and her full red lips parted in a smile at Rhys as they aimed for their thrones.
And we know he’s (very) biased, but just to end with this line since it’s so sweet:
>"You're the most beautiful thing I've ever seen. I thought that from the first moment I saw you on Calanmai." (ACOMAF, chapter 55)