恩 means debt of gratitude and is a JLPT N1 kanji. It has 10 strokes and uses the heart radical (心).
Stroke order · 10 strokes
On'yomi (音読み)
オン
Kun'yomi (訓読み)
—
Radical
心 · heart
Strokes
10
How to remember 恩
A heart (心) resting upon a cause (因) — the debt owed to whoever made you who you are today. 恩師 — a teacher who changed your life; 恩返し means repaying that debt.