Zayin in pictograph looks like a sword and the meaning of the word is sword or weapon, but the root word means sustenance or provision. The word is paradoxical. It implies that sustenance must somehow be wrested by an act of destruction of some sort.
The word which begins with zayin in this verse is 'zammah'. It means 'to consider', not in an offhand manner but to think long and deeply, with purpose and planning.
On the surface of it, this verse points out that women in that time period were able to own property in their own right. She considers a field...and she buys it. She assessed the possibilities of the land, she knew the value of it. Perhaps this was the decision that she struggled with. Perhaps the wresting has more to do with the planting: with the fruit of her hands she plants a vineyard.
A woman who plants a vineyard. It doesn't say she bought a vineyard, she bought a field. Turning a field into a vineyard is hard work. And here I think is a portion of the meaning of the paradox in zayin.
The Hebrew word which represents 'fruit of her hands' is 'peiry' and translates 'fruit of her efforts'.
The letter zayin is the seventh letter of the Hebrew alphabet and represents the number 7, and the seventh day, the Sabbath. The Sabbath day is a day of rest. The paradox of a letter that represents the seventh day in a verse about something that is clearly labor is not without purpose. Nor is the symbol of a sword, a weapon of warfare, without purpose. And let us not forget the 'sustenance' meaning of the root word. Just exactly what is going on here?
"...Man does not live by bread alone but by every word that comes from the mouth of God." Deut. 8:3
Exodus 20:8 tells us that the Sabbath day is a day of rest. I can tell you sincerely that in my experience keeping the Sabbath involves a lot of work! In order to rest on that day, I must prepare our meals the day before. I have to plan well ahead and anticipate what our needs might be (consider the field) during that day. While we are not legalistic and we do sometimes prepare food or even wash dishes if there are a good many of them, it's always a struggle to not get caught up in the busyness of the usual weekly work day and to stay mindful of the spirit of the day: to rest, restore, refresh and renew. It is a 'new crop' of sorts, a refreshed energy for the week ahead, that drives us to observe Sabbath, as much as the opportunity to spend the day acknowledging the wisdom of God's word and work in our lives. It is truth that to reach this day and fully relax, it requires a good amount of work. I find it is more than worthwhile, but there are six days to do seven days worth of work.
I believe what we see in this verse is the Proverbial woman carving out time for God, considering the goodness of her God, planting a crop of obediance thru the Torah law of keeping the sabbath. And the example she sets becomes the long lasting harvest represented by the vineyard . That example is the fruit of her efforts that comes from living righteously.