许下承诺用英语怎么说

make a promise:
作出诺言，保证

1. If you make a promise, you should fulfil it.
你苦是作出允诺，就必须履行。

2. He made a promise of help, as I pleaded with him again and again.
我再三央求，他才答应帮忙。

3. If you make a promise you should keep it; you ought not to break a promise.
如果你作出了承诺，你就应该遵守诺言，不应该食言。

commit oneself to sth.
make a commitment
make a vow
make a promise

make a promise

swear

give you my word ----- 口语

make a promise ------ 书面

Make a commitment.