"Hail, true body"
This is a direct translation, but it doesn't quite capture the full meaning and significance of the phrase. "Ave verum corpus" is a Catholic hymn, and its full meaning comes from the context of the Catholic faith. It's a hymn of adoration and reverence for the Eucharist, the body and blood of Christ.
Here are some more expressive English translations that convey the emotional weight of the phrase:
* "Hail, true Body, born of the Virgin Mary"
* "O, true Body, born of the Virgin Mary, we adore Thee"
* "Hail, holy Body of Christ, born of the Virgin Mary"
Ultimately, the best translation will depend on the specific context and the desired level of formality.