Kokoro ga Yomeru Oujo wa Konyakusha no Dekiai ni Kizukanai

Estellise, the First Princess, is skilled in a variety of magic spells. One of her worries is her fiancé, Theodore, who keeps whispering words of love to her. He uses his mind-reading magic to see into her heart, saying things like, "Estell, I love you (even though I don't really love you)." But then, her desperate feelings start to seem serious—could it be that her inner voice is wrong? (Correct) Is there a reason why she can't read his mind properly...?

A love comedy about a mistaken princess and her unfortunate fiancé!

(Source: Kadokawa, translated)