the best anime in the genre of romance?

Horimiya, Seishun Buta Yarou wa Bunny Girl Senpai no Yume wo Minai, and Oregairu.

I have to say that Horimiya was really good because unlike a lot of romance animes you didnt have to wait ages to see the confession, but that doesnt mean others arent good too. All the characters were really likeable and relatable. One that I really liked back in the day was kaichou wa maid-sama. It's pretty old now so ofc the animation does compare to anything recent but if you're looking for one of those powerful female main character then that's a good pick.

Kareshi Kanojo no Jij - from Gainax. It's freaking good