How can I get this exact tone using photoshop?? :)?

The colors appear to be desaturated, so the first thing I would try is go to Image/Adjustments/HueSaturation, and pull the Saturation handle to the left. That might be the easy fix. What may work even better, though, is if you make a new layer and fill it with a light pastel color, and then pull the opacity of that layer down (maybe somewhere around 25% - 30%). Hope this helps.