他对这件事情很狠。
tā duì zhè jiàn shìqíng hěnhěn 。
He is very ruthless about this matter.
她下定决心要狠心去做这件事。
tā xià dìng juéxīn yào hěnxīn qù zuò zhè jiàn shì 。
She is determined to resolutely do this.
他对待敌人非常狠。
tā duìdài dírén fēicháng hěn 。
He is very relentless towards his enemies.