- If you commit this card to another player's skill test, and the test is successful, you heal 1 horror (not the other player).
If this skill test is successful, heal 1 horror.
One strike against this card is that it is a skill card with a single willpower pip. The effect is, conditionally, heal 1 horror, but mystics generally have more trouble with physical damage than with horror. You would generally want 2 pips from a skill card, like Guts or from assets like Arcane Studies(2).
You can get single pips from about half of the mystic assets or events, with the upside of having another use for the card when the current problem is not the next will power test. Better skip this one and invest in Fearless(2) later, or just play allies and Painkillers to soak horror.
Fearless is a pretty straightforward card. I honestly don't see any reason not to include in any deck that relies heavely on Spells, which is to say, most decks of investigators.
Most of the Spells assets require that you do a skill test. With one icon to commit, Fearless helps you do just that, and providing you succeed, it heals 1 horror.
Some of those Spells inflict horror damage when you draw a non-numerical chaos token (example: Shrivelling), so you might want to mitigate those downsides a bit.
In any case, that card is always good encounter deck mitigation, as a lot of treacheries throws tests to the investigators, and the game has many ways to inflict horror you might want to heal.
Great great card.