心甘情愿的英文：
[Literal Meaning]
heart/willing/feeling/willing
to be willing to do something from one's heart

[解释]
心甘：乐意。心里完全愿意，没有一点勉强。

[Explanation]
to be most willing to do something

[例子]
既然你心甘情愿地参加这次活动，为什么现在后悔了？

[Example]
Since you joined this activity with all your heart, why are you regretting now?

[英文等价词]
be perfectly happy to
with one's heart and soul
with good cheer

Love is a sweet tyranny, because the lover endures his torment willingly.
爱情是甜蜜的虐政，情人心甘情愿地受它的折磨。

Promptly and cheerfully obey an order
立即心甘情愿地服从命令

He was perfectly happy to do it in this way.
他这样做心甘情愿。

He was willing to sacrifice his happiness on the altar of his fame
为了名声，他心甘情愿牺牲幸福。

She had voluntarily entered that chilling world of long silence
那时她心甘情愿跨入这个长期默默无闻的冰冷世界。

She had voluntarily entered that chilling world of long silence.
那时她心甘情愿跨入这个长期默默无闻的冰冷世界。

His willingness to work redeemed him in her eyes
他心甘情愿地干活,改善了她对他的印象。

For a small sum they were content to bargain away their happiness
为了一小笔钱，他们心甘情愿牺牲了自己的幸福。

That liBeral oBedience, without which your army would Be a Base rabble
那心甘情愿的服从;如果没有它，你们的军队将是一群卑鄙的乌合之众

He wanted a career, not a livelihood, and he was content to make immediate sacrifices for his ultimate again
他要的不是生活而是事业。为了最终的利益他心甘情愿地作出了牺牲。