Fall for someone 的含义和 fall in love with someone 相似，用来表达对某人产生了感觉、爱意，迷恋上了某人，而且是非常强烈地被这个人吸引住了。
I fell for you the first time I met you.
It took a while, but they finally fell for each other after being friends for years.
I don’t want you to fall for me. I don’t want a serious relationship.
然而，fall for something 的意思是被某事迷惑了或是被算计了、上了当，信以为真。
These days you have to be careful not to fall for phishing emails.
I told him no one had remembered his birthday. I think he fell for it, so the surprise party should really be a surprise!