の援助を当てに

rely on someone's assistance

→ の
phrase Rare #24,029
rely on someone's assistance Usually followed by する or してはいけない. The pattern Xの援助を当てにする means to count on X's assistance; 当てにする means to rely on or count on something.
JA: 彼の援助を当てにしてはいけない。
EN: You shouldn't rely on his assistance.

の援助を当てにしてはならない

You must not rely on his assistance.

そんなにたやすく他の人の援助を当てにしてはいけない

You shouldn't rely on other people's help so easily.

の援助を当てにしてはいけません

You shouldn't count on his help.

友達の援助を当てにするな

Don't count on your friends for help.

あなたは他の人たちの援助を当てにすべきでない

You shouldn't rely on other people's help.