大船 おおぶね
ōbuneni noru

Godan Verb (ru)
Idiomatic Expression

1. to gain a reliable foundation and be in a safe condition; to rest easy; to board a large ship — literal

ボクに まかせたんだ。君 きみたちは大船 おうぶね ったつもりでいるといい。
bokuni makaseta nda. kimitachiwa ōbuneni notta tsumoride iruto ii.
I'm taking care of it. You can relax. You can rely on me.