Change One's Mind, Change Your Mind
noun, verbal noun
When you flip your idea of something, you're changing how you think about it. That's why this word is change one's mind.
ほんい
This is a jukugo word that uses the on'yomi readings of the kanji. You should be able to read this on your own.
この結婚について、絶対に翻意することがないことを誓います。
I swear, I will absolutely not change my mind about this marriage.