A feeling of reassurance or security; not worried and feeling confident or safe.
貯金があると、いざというときに心丈夫だ。
Having savings makes you feel secure in case of emergency.
子どもが元気だと聞いて、母はやっと心丈夫になった。
When she heard her child was well, the mother finally felt reassured.
経験豊富な仲間がいるので、プロジェクトは心丈夫だ。
With experienced colleagues, the project feels secure/confident.