strong-willed
トムは意志が強い。
Tom has strong willpower.
おまけに彼は意志が強い。
To top it all off, he has a strong will.
彼は意志が強いんだ。
He has a strong will.
君は意志が強いな。
You have strong willpower.
意志が強いのね
You're very strong-willed.
— サスペリア (1977)