I met a woman online and I invited to my English club but she asked me to send her a few hundred yuan. I think she wanted to cheated me out of my money so I found an excuse.
I said to her "If you go to my English club, I'll do whatever you want".
I wonder if it's natural (the italic) as a reply to be the excuse that I don't want to give money to her in case she really wants to cheat me out of my money.
Is this an English question or a dating question?
The English was fine, but it was the wrong answer. It sounds like you were bartering. If she comes to the club, are you really going to give her whatever she wants?
- If you don't give her the money, it means you were lying. (That doesn't mean you have to give it to her. But at this point your integrity is on the line.)
- If you do, you might never see her or your money again. (Or she might be an angel who needs the money for her sick mother.)
Also, "I'll do whatever you want" can be wildly misconstrued or ruthlessly exploited. It's certainly not something to say to a stranger. It's fine to say it to someone you know well and trust completely. To say it to a stranger is asking for trouble.
Since you've already agreed to meet her at the club, go and see what happens. But understand that if you've already promised her money, she'll expect it.
ON THE OTHER HAND:
Several students here have said that online promises, suggestions, and proposals are idle banter and never taken seriously or literally. I don't know how true that is, but if that's the case here, then I look forward to learning how your meet-up goes!