Increasing order of solubility of ${\mathit{C}}_6{\mathit{H}}_5{\mathit{N}\mathit{H}}_2,{\left({\mathit{C}}_2{\mathit{H}}_5\right)}_2$ $\mathit{N}\mathit{H}$ and ${\mathit{C}}_2{\mathit{H}}_5{\mathit{N}\mathit{H}}_2$ are as follows:

This is because as the number of $\mathrm{}\mathit{H}$ bonded to $\mathrm{}\mathit{N}$ increases the $\mathrm{}\mathit{H}$-bonding increases which increases the solubility in water.
$\mathrm{}{\mathit{C}}_6{\mathit{H}}_5{\mathit{N}\mathit{H}}_2$ is least soluble due to presence of hydrophobic benzene ring in the skeleton of structure.