“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.
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.
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.
He is very smart and willing to endure hardship.
1.tā zài xuéxí shàng zǒng shì bù______xià gōngfū.
2.suīrán zhè jiàn shì hěn máfan, dànshì wǒ fēicháng_______qù zuò.
3.shì wǒ zìjǐ _______ de, méiyǒu rén qiǎngpò wǒ.