By comparing the
Heritage site plan and
Wake County's iMAPS, it looks like almost all of it is in Wake Forest.
In the southeast corner of the map, the southern part of Evening Snow St is in Rolesville, and the neighborhood on the east side of Rogers Rd (which includes Corner Rock, Heritage Gates, Lawson Walk, etc) is in Rolesville.
Your taxes will be a little more expensive in Wake Forest.
(Tax table) Which town you live in determines which police department responds, which fire department is primarily responsible for responding, who collects the trash, etc. (Water and sewer are provided by Raleigh, no matter which of those two municipalities you live in)
As Meh mentioned, the "city" part of the mailing address doesn't matter one bit in all of this. That is just determined by which post office happens to deliver the mail. So you could live in the Wake Forest town limits with a Rolesville mailing address or vice-versa. Because of the confusion over that issue, you may want to use the iMAPS link above and double-check any properties you're interested in, to make sure you know whose town limits it is in.
I hope that helps.