心に決めている

be determined

→ 心
phrase Rare #42,233
be determined Indicates that someone has made a firm decision or is resolved to do something. Often followed by と or ようと.
JA: 今年こそ日本語を話せるようになると心に決めている。
EN: I’m determined to be able to speak Japanese this year.

彼女は今度はうまくやろうと心に決めている

She is determined to do better this time.

彼女は会社を辞める心に決めている

She has made up her mind to quit her job.

彼は教師になろうと心に決めている

He has made up his mind to become a teacher.