Correct

发狠

/ fà hěn / 
Strokes

Example

As a Verb

make a determined effort; strive resolutely

1
Tā
他
yī
一
fàhěn
发狠
  
,
shuí
谁
yě
也
lán
拦
bù
不
zhù
住
  
。

Once he resolves on doing it, nobody can dissuade him.

2
Tā
他
wéi
为
mǎi
买
yī
一
bù
部
chē
车
ér
而
fàhěn
发狠
gōngzuò
工作
  
。

He is working like crazy in order to buy a car.

3
Fàhěn
发狠
jièyān
戒烟

resolve to quit smoking; make a determined effort to give up smoking; be dead set to quit smoking

As a Verb

be/get angry; flare up; be furious

4
Biè
别
yǐwéi
以为
nǐ
你
yī
一
fàhěn
发狠
jiù
就
bǎ
把
tāmen
他们
hè
吓
pǎo
跑
le
了
  
。

Don't assume that your anger will frighten them off.