Fall for something意為allow oneself to be persuaded by something，相信某事。

例：

The salesman said the car was in good condition, and I was foolish enough to fall for it.

營銷推廣員說這輛汽車情況好， 而我竟傻到信以為真。

例：

Im surprised you fell for that trick.

真不敢想象你居然相信這個騙局。

Fall for somebody也就是fall in love with somebody，被某人所吸引，愛上某人，迷戀某人。

例：

They met, fell for each other and got married six weeks later.

他們兩個一見傾心，6個星期后就結了婚。