The reward halving is going to help Gulden maintain a good price in the next bear market. Bitvavo will also help.
Both will (in theory) result in an increase of the price. First thing up is the reward reduction of around 25%. If the current demand remains the same, the price should in theory increase from the moment on this reward reduction takes place. The first reward halving is after that a couple years away from now, but definitely something to look forward to.
Also I believe the demand for Gulden will steadily grow over the upcoming months/years. So I think the first reward reduction of around 25% will have a bigger impact than the market currently is showing.