I did not think that you knew the letter Æ. Then I should have used it in my reading of the Danish text.
So aerlig=ærlig, Aegteskab=Ægteskab, naest=næst and of course Skiaer=Skiær.
The test is;
3. Mandag. d. 27de Jan blev Mads Skærs Enkes
liig ved 12 Ringning begravet uden de 17 Al.
3. Monday, Jan. 27nd was Mads Skærs widdows
body (or dead body) by 12 rings (12 strokes from the church bell) burried without (or outside) the 17 al.?
age. (not written the age).
I think that "outside the 17 al." refers to a specific area in the church yard.
In those days they paid to let the bell ring, and paid for songs at the burial, so this is mentioned.
The two witness at the betrothal; Peder Wibe and Madssen Skiær
Madssen could be a mistake, and there it should have been Mads. This fits to Jens Madssen Skiærs name; Jens son of Mads, because Madssen=Madssøn= Mads' Søn which is the son of Mads
But it could also be as written Madssen Skiær with no forename mentioned. Then it could be a brother of Jens Madsen Skiær.
Anyway the Mads Skær in the burial could be your Jens Madssen Skiærs father, and then it could be his mothers (or stepmothers) dead.
I guess, that it is his father (as a witness and in the burial). And then he must have died before 1777. But you have to investigate this more to be sure.