There is really no one who can promise this. The voters supporting both projects are diverse Steem stakeholders who are expressing their view that the projects are a better use of rewards funds than a lot of other posts.

When it was mostly just a few whales and old timers supporting burnpost the payouts were $20 or less (at or near the current STEEM price), and while technically on Trending, it wasn't on the first few pages (I helped with this by voting on day 3, which I still do, actually day 4 now), but once the payouts increased to $50 or more, that's from a lot of different voters.