We're down to the last daughter, and she's a smart girl, because she's learned from example. No poverty, exile, disinheritance, or drowning for her. No way. She's going to marry the rich contractor and have a nice, comfortable life.
So, we know that she doesn't want to rock the boat. Other than that, it's hard to know what to make of Beilke. Tevye sure can't figure her out. Check out the section where he gets her mood totally wrong:
Beilke would rather die than go through with the marriage. The more Podhotsur showered her with gifts and gold watches and diamond rings, the more he revolted her. She didn't have to spell it out for me. I saw it in her face and in her eyes and in her silent weeping. […]
"Don't compare me to Hodl," Beilke said. "Hodl lived at a time when the whole world was in chaos, about to turn upside down, and people were worrying about that and forgetting about themselves. But now," she said, "that the world is calm again, everyone is worried about himself, and they've forgotten about the world." (8.45-52)
Are you sure that she doesn't need to spell it out for you, Tevye? Because it seems like you don't have the slightest clue. Podhotsur doesn't revolt her at all. It turns out that she actually kind of likes the guy.
When she explains herself, she seems really clear-eyed and practical about her choice, and it even sounds like she sees her sisters' marriages as selfish. But how are we meant to read her decision? Is she wise beyond her years? Self-sacrificing? Trying not to repeat her sisters' mistakes?
Whatever the answer is, it turns out that Beilke's big sacrifice is a bust. Sure, Podhotsur's wealth gets Perchik out of prison and off to Japan, where presumably life is at least a little better than in Siberia. (At least, you have to think the food is better.)
But after Podhotsur's business fails, Beilke has to follow him to a horrible fate working in a factory in America, and she doesn't even love the guy.