1To understand or be aware of a matter or situation, and to grasp it properly.
ベテラン社員は取引先の事情をよく心得ている。
The veteran employee understands the client's circumstances well.
新人は現場の作法をまだ心得ていないようだ。
The new employee doesn't seem to grasp the customs of the workplace yet.
彼女は空気を読むことを心得ていて、場を和ませるのがうまい。
She knows how to read the room and is good at putting people at ease.
2To knowingly accept and take on a duty or responsibility.
彼は後任として店の運営を心得ることになった。
He took on the running of the store as the successor.
その役目を心得た以上、途中で投げ出すわけにはいかない。
Once you've accepted that role, you can't just abandon it halfway.
3To have mastered a skill or art well enough to perform it competently.
祖母は茶道の作法を心得ている。
My grandmother has a good command of the etiquette of tea ceremony.
彼は応急手当を心得ているので、いざという時に頼りになる。
He knows how to give first aid, so he's dependable in an emergency.