解析如下：

1. 第一，大众情人叫做 lady killer;

A lady killer refers to a man who's extremely charming and women just throw themselves at him. These guys are usually very good-looking.

Eg: Every girl dreamt of dating him in college. He's such a lady killer! 尽管如此，他人却特别随和，一点也不难伺候!

2. 第二，形容某人难伺候可以用 high-maintenance;

I didn't know that your boyfriend is a high-maintenance guy.

when you say someone is high-maintenance, it means he or she is really hard to satisfy. 就是难伺候！

Eg: My boyfriend is definitely high-maintenance.

3. 第三，配不上，叫做 out of someone's league!

You can say A is out of B's league. 意思就是A配不上B。