That store makes the customers buy things that they don't really need by making them believe that they need them.
こんにちは。
ご質問ありがとうございます。
"That store makes the customers buy things"＝「あの店は客にものを買わせているよ」
"that they don't really need"＝「彼らが本当は要らないものを」
"by making them believe that they need them."＝「彼らがそれらを必要だと信じさせることによって。」
ご参考までに。
That store gets its' customers to buy unnecessary things with their silver tongue.
"あの店は上手く話して必要ないものを客に買わせてるよ"
- That store gets its' customers to buy unnecessary things with their silver tongue.
あの店は本当は必要ないものなのに、色々といるように客に信じ込ませて買わせている
- That store really convinces customers to buy things that they don't need, but they make the customers believe they need them and convince them to buy.
The people who work at that store are good at talking people into buying things they don't need.
この場合、次のような言い方ができます。
ーThe people who work at that store are good at talking people into buying things they don't need.
「その店で働いている人たちは、必要のないものを買わせるのが上手い」
to be good at ~ing で「〜するのがうまい」
to talk someone into ~ing で「人にうまく話をして〜させる・人を〜する気にさせる」
ご参考まで！
アメリカ合衆国 
カナダ 
