swear

To make a solemn declaration, invoking a deity or a sacred person or thing, in confirmation of and witness to the honesty or truth of such a declaration.

To make a solemn promise; vow.

To use obscene or blasphemous language; curse.

To commit oneself by oath to giving evidence or testimony that is truthful.

To declare or affirm solemnly by invoking a deity or a sacred person or thing.