The Sacred Blacksmith Vol 1

The Sacred Blacksmith by Isao Miura. A Fantasy manga rated Older Teen, published in English by Seven Seas.

Cecily Campbell is a young knight determined to protect her city, though her swordsmanship hasn't caught up to her ideals. She's saved by Luke Ainsworth, a talented blacksmith who forges swords with his mysterious assistant Lisa, and asks him to make her a blade.