How to say "Completion" in Japanese

When translating "completion" into Japanese, you must choose carefully between 完成 and 完遂. In Japanese, 完成 (かんせい (kansei)) is typically associated with "completion; perfection; accomplishment" (Syllabus Level: N3) and represents Refers to completion, perfection, or accomplishment of a product, project, or setup. Often used as 完成させる or 完成品. ⚠️ Haruka's Voice Column: 'Completion! "The cake for Haruka-san is complete!" ...っ, T-To make a cake just for me! B-But our relationship won't be "complete" until you marry me!' / 【ハルカ部長のワンポイント指導】『かんせい（完成）！『ハルカさんのための特製ケーキが完成しました！』って…っ, 私のためだけにケーキを完成させるなんて！でもね、私たちが結婚するまで、私たちの関係は『未完成』なんだからね！』. On the other hand, 完遂 (かんすい (kansui)) maps to "completion, accomplishment, achievement (of a task, duty, etc.)" (Syllabus Level: N1) and represents Implies successfully finishing a task or goal, often one that was difficult or required persistence. It has a nuance of completing something to the very end. 困難な目標や任務を最後までやり遂げること、達成することを指します。強い意志や努力が伴うニュアンスがあります。. A literal translation of "completion" can often sound unnatural to native Japanese speakers if mixed up!