。
Try to see things as they really are.
Literal
Things [object-を] as-they-are see.
ありのまま means 'as it really is' — closely related to あるがまま but more common in everyday use, famous from the Japanese version of 'Let It Go' (ありのままで). ~なさい gives a mild command. に makes it adverbial: 'in a way that is as-it-is.'