Correct

上刀山,下火海

/ shàng dāo shān xià huǒ hǎi /
Strokes
https://i.cchatty2.com/filters:format(webp)/fit-in/684x0/img/202102/上刀山下火海-Chinese-idioms-Cchatty-407934e0-c455-478f-b6db-16ef72819172-1612776167.jpg

Collocation

1
用不着上刀山,下火海
2
就是让他上刀山,下火海,他也愿意

Definition

上刀山,下火海

Literally means:

explore mountains of swords and seas of flames

Actually means:

do a most dangerous and difficult thing

It means one is so brave as to do difficult or dangerous thing regardless of his own safety. It carries a sense of exaggeration.

比喻不顾自己的安全去做艰难而危险的事情。带有夸张的意味。

Example

Used as predicate or object. (作谓语、宾语)
1
yǒnggǎn
勇敢
zhì
机智
  
,
jiùshì
就是
shàng
dāoshān
刀山
  
,
xià
huǒhǎi
火海
  
,
huì
píngān
平安
huílai
回来
de
  

He is brave and witty, that is, up the knife mountain, under the sea of fire, will also come back safely.

2
Zhǐyào
只要
néng
zhuā
dào
shāhài
杀害
qīnrén
亲人
de
zuìfàn
罪犯
  
,
哪怕
shì
ràng
shàng
dāoshān
刀山
  
,
xià
huǒhǎi
火海
  
,
yuàn
愿意
de
  

As long as he can catch the criminal who killed his loved ones, even if it is to let him go up the knife mountain, under the sea of fire, he would like to.

3
yào
zuò
de
shì
diǎn
wēixiǎn
危险
  
,
yòngbuzháo
用不着
shàng
dāoshān
刀山
  
,
xià
huǒhǎi
火海
  
,
zhǐyào
只要
yānjiǔ
烟酒
jièdiào
戒掉
jiù
háng
le
  

What I want you to do is not dangerous at all, do not need to go up the knife mountain, under the sea of fire, as long as you give up smoking and drinking on the line.