In all the instances of "Troth" in those two wills the first letter is a form of "T" that was fairly common at the time. The bit on the front was written by a different person, but you can tell it's a "T" because the abbreviated word before the name is "Tm" (standing for Testament) and the first letter is the same as in the name.
The form used within the wills is quite similar to an "E" but if you compare it with the first letter of "Executor" you can see an important difference. The "T" is composed of two strokes, with the pen taken off the paper in-between, while the "E" is one stroke made up of two curves.
Troth was a fairly common name in Derbyshire. If you search Ancestry's index of early Derbyshire parish registers for Troth you get over 200 records, adding Troath and Truth puts it up to about 300.
Searching for Eroth or similar gives just 6 records, and on inspection every one is a misreading of Troath!
David