
Spoiler
.
.
.
.
.
.
.
.
.
.
.
Lancelot actually found the real Charlotte with his magic, he went to go get her, but was stop by a demon who the real Charlotte made a contract with to be the princess. When Lancelot found out that he was abandoned again by someone he loves, he decided to disappear. However the new Charlotte comes all worried that he left without telling her and tells him to not disappear again. Lancelot decides to stay with the new Charlotte because he thinks she's interesting and that she's the only one who cares about him. That's why he decide to be engaged with her, he doesn't really like her now, but later on will fall in love with her.
So..... I really don't know Lancelot's intentions by becoming engaged with the mc knowing full and well that she isn't the same as lady charlotte. I'm very open to spoilers if anyone has any.