Here are some examples for you:
1. Your father is not coming, so she has a hu*****and (family tie) staying in China.
2. Her company can provide some type of letter to prove that she will return to her job
3. She has other properties such as money in the bank, other investment,etc.
The most important, is to appear confident and speak the truth, the VO will definitely reject if he/she suspect any lying or in-confidence.
Good luck!