くれぐれもrepeatedly, sincerely, earnestly

くれぐれも体調(たいちょう)に気(き)をつけてください。

Please sincerely take care of yourself.

くれぐれも餅(もち)を喉(のど)に詰(つ)まらせないようにね！

Make sure the mochi doesn't get stuck in your throat okay?

先(さき)にお伝(つた)えした通(とお)り、くれぐれもご両親(りょうしん)によろしくお伝(つた)えください。

As I said before, please give my sincere regards to your parents.

くれぐれも気(き)を付(つ)けるようにすると共(とも)に、全力(ぜんりょく)で楽(たの)しんできてね！

Be sure to earnestly take care and have all the fun you can!

道路(どうろ)を渡(わた)るときはくれぐれも左右(さゆう)に気(き)を付(つ)けるだけでなく前後(ぜんご)にも気(き)を付(つ)けてください。

When crossing the road, please be sure to be extremely cautious not only about left and right but also about the front and back.