In astrological tradition, the Rising sign (the Ascendant) is the sign that was on the eastern horizon at the moment of birth. It is often read as the "first impression" — the style someone leads with and the lens through which they meet the world.
With Pisces Rising, that first impression is often read as empathic, imaginative, gentle, and boundary-soft. As a water sign, Pisces tends to give the outward manner a empathic, imaginative cast, and tradition associates this Ascendant with a gentle approach to new situations and new people.
Because the Ascendant depends on an accurate birth time, a Rising sign cannot be guessed from a birthday alone. These are the general tendencies astrologers associate with Pisces Rising — not a prediction, and not a substitute for the full chart that places it among the houses and aspects.
A general guide to astrological tradition — tendencies, not predictions. It describes the placement in the abstract and is not about any specific person.