I only read about the first two chapters like a year ago so I don't remember well, but if I remember correctly the protagonist had long blue hair at the beginning and everything was fully colored. She was some sort of Saint, had magical power and was gonna be the ruler of a kingdom I think.
She, her partner and her male friend (I think he had either dark brown or red hair) were the ones who freed said kingdom, and she thought everything was fine. Then, one day, she overheard her partner and friend having a talk, during which she hears them apparently saying that they love each other. She's shocked and leaves. Later on, she's betrayed by the two males and killed or sealed; not too sure.
Then she's reborn hundreds of years later. Both her ex-partner and friend are dead since long ago, and the protagonist is a baby/small child now who appears in some sort of church or palace and is received by someone from the royal family, if I'm not mistaken.
I might not be remembering everything correctly, but please, if someone knows the title or what might it be I'd be really really thankful. <333