肯 vs 愿意 vs 情愿

肯 (kěn), 愿意 (yuànyì) and 情愿, these three words all express "willingness", but they differ in tone, emphasis, and usage.

1. 肯 (kěn) – "Willing to (after persuasion or reluctance)"

Meaning:

• Implies initial reluctance or requiring persuasion before agreeing.
• Often used when someone finally agrees to do something.
• Can also mean "to consent" or "to be willing to put in effort."

Usage:

✅ After persuasion/reluctance:

• 他一开始不肯帮忙，后来才肯。 (At first, he wasn’t willing to help, but later he agreed.)
• 她怎么也不肯认错。
  (She refused to admit her mistake no matter what.)

✅ Willing to endure hardship:

• 他很肯吃苦。 (He’s willing to endure hardship.)
• 她肯下功夫学习。 (She’s willing to put in effort to study.)

❌ Not used for strong personal desires:

• ❌ "我肯去旅行。" (Wrong – use 愿意 instead.)

2. 愿意 (yuànyì) – "Willing to (neutral or positive willingness)"

Meaning:

• General term for voluntary willingness.
• No implied reluctance – simply agreeing or wanting to do something.
• Can be used for personal desires, preferences, or polite agreements.

Usage:

✅ Neutral willingness (no reluctance):

• 我愿意帮你。 (I’m willing to help you.)
• 你愿意和我结婚吗？ (Would you be willing to marry me?)

✅ Preferences & desires:

• 我愿意学中文。 (I’m willing to learn Chinese.)
• 他不愿意吃辣。 (He doesn’t want to eat spicy food.)

✅ Polite offers/requests:

• 你愿意试试吗？ (Would you like to try?)

3. 情愿 (qíngyuàn) – "Willing to (with emotional or personal sacrifice)"

Meaning:

• Stronger than 愿意, often implying personal sacrifice or emotional willingness.
• Used when someone chooses one option over another, even if it’s not ideal.
• Often appears in "宁可…也情愿…" (would rather… than…) structures.

Usage:

✅ Sacrificial willingness:

• 我情愿少赚钱，也要做喜欢的工作。
  (I’d rather earn less money than do a job I don’t like.)
• 他情愿自己受苦，也不让家人担心。
  (He’d rather suffer himself than let his family worry.)

✅ Preference structures:

• 我情愿走路，也不坐他的车。
  (I’d rather walk than ride in his car.)

❌ Not for casual willingness:

• ❌ "我情愿帮你。" (Unnatural – use 愿意 instead.)

4. Key Differences Summary

5. When to Use Which?

Use 肯 when:

• Someone finally agrees after reluctance.
• Someone is willing to endure hardship.

Use 愿意 when:

• Expressing general willingness or preference.
• Making polite requests or offers.

Use 情愿 when:

• Someone chooses one thing over another.
• There’s emotional or personal sacrifice involved.

Final Tip:

• 肯 = Agrees after reluctance / willing to endure.
• 愿意 = General willingness (neutral).
• 情愿 = Emotional willingness or sacrifice.