Purvis has never shot above 39% from deep, what makes you think that he will improve that much? Completely unrealistic prediction/expectation IMO. Who is the last UConn player to shoot anywhere close to 45% at high volume besides Giffey? I can't think of a single guy who has been that efficient from long range in the last 10 years.
FWIW
Hield's 3p%
Fr - 23.8%
So - 38.6%
Jr - 35.9%
Sr - 45.7%
(Edit: I don't "expect" 45%+. 42%+ would make me happy)