If you have a trust fund, you should be able to hire a lawyer, and I suggest you do. Even if the trust is not paying out at present, she may be able to collect on future payments. Especially if you have children in common.
Any financial obligations you owe your ex-wife, such as child support or consideration for transfer of an interest in real estate, should be set forth in your separation agreement and court orders accompanying your divorce decree. Generally, as part of a divorce proceeding the parties execute a mutual general release agreement resolving all past and future claims and obligations between them.
You should review any documents provided by the court at the time of your divorce. If you don't have copies you can visit the court and request the file. You can obtain copies of the decree and agreement. You should also contact the attorney who represented you at the time of your divorce.
If you were not represented by an attorney at the time of your divorce and/or if you did not disclose your income from the trust, you need legal advice now. You should contact an attorney who specializes in divorce in your area who can review your situation and explain your options.