Correct
铁心
/ tiě xīn /
Strokes
Example
As a Verb
cling to one's determination; be unshakable in one's determination; be immovably determined; have firm determination; be resolute
1
Zhè
这
huí
回
tā
他
kěshì
可是
tiě
铁
le
了
xīn
心
lā
啦
。
He is unshakable in his determination this time.
2
Tiěxīn
铁心
jīngshāng
经商
be determined to go in for business
As an Adjective
heart of iron/stone/granite—ironhearted; hard-hearted; heartless
3
Tiěxīnrén
铁心人
heartless person
As a Noun
(iron) core
4
Tiěxīn
铁心
xiànquān
线圈
iron core/magnet coil