Bottom Of One's Heart
Bottom Of My Heart
adverb, noun
The heart bottom is the bottom of one's heart. Do you want to learn kanji? Do you want to learn it from 心底? Okay, fine, you can move onto the reading then.
This word uses the on'yomi reading for the first kanji and the kun'yomi reading for the second kanji. You've learned them both already, so you should be able to read this too!
コウイチの不治の病が治って、心底うれしいよ。
I'm sincerely happy that Koichi's incurable disease actually has been cured.
彼の発言を聞いて、心底気持ち悪いと思いました。
I found his statement to be sincerely sickening.
新しいチーム、みんな良い人ばかりで、心底ホッとしたよ。
I felt really relieved that everyone on the new team are such nice people.