When you place an onion cell, which is composed of 95% water and thus has a lower concentration of salt (solute), in a 10% saline solution (which has a higher concentration of salt), water will move out of the cell due to the process of osmosis. Osmosis is the movement of water across a semipermeable membrane from an area of lower solute concentration (inside the cell) to an area of higher solute concentration (outside the cell) in order to equalize solute concentrations on both sides.
Therefore, you would expect:
Water to leave the cell.