It really isn't anything easy to answer. I, myself, have flipped back and forth. I suppose having the life to still live after this tragedy makes up for the 10 years of torture.
If it were simply a matter of living secretly away from you and never hearing from her again versus death, I'd give up my peace of mind for her life. Even if it meant that I would never hear from her, or know her fate, I'd rather her be alive and on her own. After all it's the imagined fate I had for my sister before she was found.
I certainly wouldn't wish either on anyone's family. The only thing I can say for a fact, knowing their fate brings it's own peace.
"I would rather be exposed to the inconveniences attending too much liberty than to those attending too small a degree of it." Thomas Jefferson