気にしないでね　大丈夫だよの表現

(1) 約束していたのに相手の体調等が悪く実行されなかったとき
No worries. Your health comes first.
It’s totally fine. Take care of yourself.
It’s all good. Your health is important.
Don’t sweat it. Take the time you need to feel better.

(2) 手伝ったのでお礼を言われたとき
You’re welcome. It was my pleasure.
No worries. Glad I could help.
Don’t mention it. Happy to lend a hand.