Correct

怀疑 vs 疑心

/ huáiyí vs yíxīn /
Strokes

Definition

怀疑 is a Verb and 疑心 as a Verb or Noun, which means [doubt; suspect; suspicion].

Example

怀疑 and 疑心 as verbs, means to "have doubt in a person or thing". They are interchangeable.
1
diǎnr  
一点儿
huái
怀疑
  
(
xīn
疑心
  
)
de
zhēnchéng
真诚
  

I don't doubt his honesty at all.

2
zǎojiù
早就
huái
怀疑
  
(
xīn
疑心
  
)
zhè
fēng
xìn
shi
xiě
de
  

She was suspicious early that the letter was not written by him.

怀疑 can be used in the passive voice, but 疑心 cannot.
3
chéng
le
bèi
huái
怀疑
de
duìxiàng
对象
  

He became the suspect.

怀疑 can used as the objects of 凭.
4
Zhī
píng
huái
怀疑
néng
gěi
rén
dìngzuì
定罪
  

It is reckless that convicting a person by mere suspicion.

疑心 is also a noun, but 怀疑 is not.
5
Zhège
这个
rén
xīn
疑心
tài
chóng
  
,
duì
shénme
什么
rén
dōu
fàngxīn
放心
  

The man is too suspicious to believe everyone.

6
Àn
案发
hòu
  
,
de
biǎoxiàn
表现
yǒuxiē
有些
cháng
异常
  
,
yīnér
因而
biéren
别人
duì
le
xīn
疑心
  

He was doubted by others because of his abnormal behavior after the case.