funny. the manhwa is a lot more romantic than the novel. the novel would basically say that she's irreplaceable because of her skills and knowledge so the care and love ML felt for her basically... wasn't there. even if he felt it, it was always covered with 'duty'. and MC's inner monologues about how she's only useful for her support mage skills and knowledge about the 'future' and about how ML doesn't actually care about her as a erson... which he always sort of confirmed. it was only in the last couple of chapters that anything romantic even happened, the dungeon crawls and revenge against the red-head OG!'hero' were the main plot drivers. here, mayer is basically salivating over her at every moment lol :D
He's being vulnerable and sweet on one hand but on the other they are there for a reason and her mission and desire to improve is important. She not something to be squirrelled away and kept in a glass case to appease his feelings. It's a slippery slope and she's got her priorities!!! We'll see tho lol