You know what would be perfect for him? A girl that 'mirrors' him. That thinks that the world is full of girl love. She can think of him as a 'supportive brother' trope for example and our lead doesn't have to break his own rules.
Our protagonist will have to live without close friends of either gender at this rate. He can even have a distant harem. Similar to Link in Breath of the Wild isn't it. A true wizard of his own making.
This manga seems to have been inspired by the older mangas. Even to the basic personality traits that were common at one point. Back before the term "isekai'd" was even used. Think of animes like Escaflowne.
What is also sus is the fact that her character has no past. No childhood friends for example. I bet that the father is a priest, not her birth father. He could of just introduced himself as a father and she mistook that to mean he is her character's actual father. The church just rolled with...
I wonder if the pills help to reanimate her body. She was technically dead (or so we are told). What if she isn't a reincarnation, but the original being strengthened bit by bit?
On a different point, I hope she does fall in love with her future husband.