This is the 1077th most frequent Japanese word.
決意
"決意" means "determination" or "resolution."
In this sentence, "決意" (decision/determination) is used to express the person's resolve to undertake a new challenge starting from the next year.
来年から新しいスキルを身につけることを決意しました。
I decided to acquire a new skill starting next year.
Here, "決意" is used to describe the abstract quality of determination perceived in someone's demeanor.
彼女の目からは強い決意が感じ取れました。
A strong sense of determination was felt from her eyes.
In this usage, "決意" refers to the essential attribute or mental resolve required to face and surpass challenges.