When V2 raises, especially with his sizing, we're generally drawing to one out here. NFDs would raise much larger, 2P is probably not in his PF range, and usually doesn't raise flop anyway. Sets might raise flop, and would take this line pre-flop, however they don't raise here 100% of the time, and they still have a decent amount of equity against us.
V1's range for betting flop then just calling is probably an over-pair with a heart, or AhXx, but there's a non-zero chance of him having the nut-flush here.
I put our hand against these ranges, and even if V2 raises all sets here, if he calls all AhXh, all broadway heart combos, and all suited heart connectors, we only have 20% equity against both their ranges.
http://www.pokerstrategy.com
Board: 2h3h6h
Equity Win Tie
UTG 20.60% 20.50% 0.09% { 5s4h }
UTG+1 21.86% 21.76% 0.09% { AdAh, AhAs, AhAc, KdKh, KhKs, KhKc, QdQh, QhQs, QhQc, JdJh, JhJs, JhJc, TdTh, ThTs, ThTc, AhKh, AhQh, AhKd, AhKs, AhKc, AhQd, AhQs, AhQc }
UTG+2 57.55% 57.46% 0.09% { 66, 33-22, KhAh, QhAh, JhAh, ThAh, 9hAh, 8hAh, 7hAh, 6hAh, 5hAh, 4hAh, 3hAh, 2hAh, KhQh, KhJh, QhJh, KhTh, QhTh, JhTh, Th9h, 9h8h, 8h7h }