Using an experimental trust game, we investigate whether guilt-aversion motivates individuals to keep their promise. In our modified trust game, we allow the trustor to purchase insurance in case of a non-performance by the trustee. In our design, the purchase of insurance signals lower expectations from the trustee as compared to no insurance purchase. We find evidence that purchase of insurance lowers the rate of promise keeping, consistent with the guilt-aversion motivation. The design also opens up a richer set of message strategies that a trustee can use to persuade the trustor. We find the use of a conditional promise - a promise to choose the non-selfish action only if the trustor chooses not to insure - avoids the moral obligation that arises from sending a promise. Surprisingly, conditional promises increase the number of efficient outcomes more than the conventional promissory language