When you're at an interview, and the firm ask you to state your expectant salary, you should refuse.
Tell the interviewer to pay what they think you're worth. They are in the best position to know your salary, not you. You can negotiate later after you know the amount.
If the amount is not justified, the employee will jump ship eventually in the future. It's not about the amount, in Singapore it's not difficult to find a job, it's about the integrity to pay someone what he or she is worth to the company.