“愿意(yuànyì)” and “肯(kěn)” are both auxiliary verbs, both of which indicate the general compliance with demands or willingness to do something.
“愿意(yuànyì)” is used to express how someone feels, particularly a feeling of acceptance or desire to do something without feeling unhappy. It can also be modified by placing adverbs of degree, like “非常(fēicháng)” or “很(hěn)”, in front of it.
wǒ fēicháng yuànyì bāngzhù nǐ.
我非常愿意帮助你。
I am very willing to help you.
“愿意(yuànyì)” demonstrates a higher level of willingness on the part of the subject than “肯(kěn)”. When using “肯(kěn)”, we don’t really know how willing someone is to do something.
“肯(kěn)” can be used in two situations.
The first is to indicate acceptance of a specific thing at the request of others, and without any adverb of degree in front of it.
wǒ quàn le hǎojiǔ, tā cái kěn qù cānjiā huódòng.
我劝了好久，他才肯去参加活动。
It took me a long time to persuade him to join in the activity.
The second situation has nothing to do with a specific demand, it’s more a commentary on the person simply being willing to give. In this case, 肯(kěn) is equivalent to “愿意(yuànyì)”, and can be modified by an adverb of degree in front of it.
tā hěn cōngminɡ, yòu hěn yuànyì/kěn chīkǔ.
他很聪明，又很愿意/肯吃苦。
He is very smart and willing to endure hardship.
A.愿意(yuànyì)
B.肯(kěn)
1.tā zài xuéxí shàng zǒng shì bù______xià gōngfū.
他在学习上总是不______下功夫。
2.suīrán zhè jiàn shì hěn máfan, dànshì wǒ fēicháng_______qù zuò.
虽然这件事很麻烦，但是我非常_______去做。
3.shì wǒ zìjǐ _______ de, méiyǒu rén qiǎngpò wǒ.
是我自己_______的，没有人强迫我。
How to express different levels of understanding: 理解 VS 了解
When and How to Use “不 (Bù)” and “没 (Méi)” for Negative Meaning
Frequency Words: “经常(jīngcháng)” vs. “通常(tōngcháng)”
