
if you want to marry the witch you better marry all of the witch you damn prince
but isn't the prince and Nightingtale kissing too ?

.
.
.
.
.
.
.
.
.
.
.
.
.
.
Anna is #1 best girl, he had deep technical conversations with her and they even reach a point in their relationship where they sleep together. Nightingale, as May's foil, is in an unrequited relationship... At first. Being super loyal and always by Roland's side, he eventually acknowledges her feelings for him. Anna isn't against it but doesn't really like it at first. She asks for some time to get used to the idea of him not just being hers but is glad that he would choose Nightingale of all people to be a second lover as she loves her like a sister.
The author makes it clear that it's not a harem route with all the witches but rather a respectful love between Anna, Roland, and Nightingale. The author also makes it clear that Nightingale's blinding loyalty makes her fit to be the head of the kingdom's internal police/investigations department/shadow core/whatever you wanna call it, but a terrible queen as she has tunnel vision for Roland when things go awry. Anna on the other hand, is shown to make an excellent queen as when things go south, she keeps her head and is able to protect Roland along with everyone else.
It's also common in that world's (or at least Greycastle's) culture for noblemen and even wealthy merchants to have multiple wives. The previous king, Roland's father, was a rare exception as he only took one wife, the queen, and refused to get married after she died. So in actuality, people find it more strange that Roland, who is still known by his womanizing rumors, to only have one lover. They actually find that more strange than the fact that she is a witch. What they find the most strange, is the fact that he hasn't taken a normal woman lover since his other two lovers are witches. Witches cannot bear children which created a succession problem. This would normally be mitigated by a relative taking the throne but his only living relative who isn't an enemy is his sister Tilly, also a witch. There are two ways to resolve this but one of those ways is a major spoiler that has only barely been touched on in this manhua and has little to do with your question.
i'm soooo fucking love this
they two make a good comrade ヾ(☆▽☆)