does anyone know the difference between the 2?

The simplest explanation is reasonable suspicion is a lower standard then reasonable grounds. Suspicion is the threshold that can allow police to proceed with an investigation, and reasonable grounds is the threshold to proceed with a charge.

One example would be if you're a G2 driver stopped by police at a RIDE checkpoint. The officer asks you if you've had anything to drink. You say no, but the officer thinks he can smell alcohol on your breath. He can't charge you for the novice violation at this point, he only has a suspicion you've been drinking. It's possible that the odour could be coming from one of your passengers, or maybe someone at the party spilt beer on your clothes. But because the officer does have a suspicion, he demands you provide a breath sample. You blow into a roadside screening device and it shows your blood alcohol content is well above zero. The officer now has reasonable grounds to believe you've committed the novice violation and charges you.