If you sell at a gain then absolutely. You will pay taxes on the gain. As for determining the taxable gain, you first have to determine the cost-basis. Usually, when one inherits property the cost basis is the FMV at the time of the passing of the deceased. But since the trust owned the house and not your mother at the time of her passing, how the cost basis is determined has nothing to do with the date of her passing. It will depend on how the trust was set up. This has the potential to make the cost basis lower, and your taxable gain higher.
One thing you "might" be able to do is that *you* not inherit the house prior to selling it. Let the trust sell the house, then let trust pay any capital gains on the sale, and you inherit what remains.
But again, what's best and what can legally be done with that scenario, and what's best tax-wise depends on how the trust is set up. You'll have to contact the administrator of the trust. If that's you and you don't know,. then you'll need to seek the services of legal counsel or a CPA in the jurisdiction of the trust, who is well versed in such scenarios.
