Problem with hero losing lives

First off, have you already created the event where the hero destroys the enemy? If you have, then what you need to do next is make a change to the event where the hero does lose a life. Add a new condition by right-clicking on an existing condition in the event where the hero loses a life, right-click on the hero object, move your mouse over the "Animation" sub-menu, click on the "Which animation of "Hero" is playing?" menu option, then select the "Stabbing" animation. After that, right-click on the newly-added condition (the one where it tests to see if the hero object's animation "Stabbing" is playing), then click on the "Negate" menu option. If you haven't already created the event where the hero destroys the enemy, then let me know so that I can tell you how to create the event where the hero destroys the enemy. You will still need to do what I said above anyway, it's just that what I said above won't make the enemy get destroyed when the hero is playing the stabbing animation, it just makes it so that the hero doesn't get hurt when it is stabbing.