The cherry flavour exists to make the sublingual tablets more pleasant to hold in the mouth. Pure glycine has a slightly sweetish taste, but some adults find neutral pharmaceutical tablets unpleasant to keep in the mouth. Because these tablets are meant to dissolve slowly under the tongue, an agreeable taste makes the process more comfortable.
The product description says the flavour is natural cherry flavour, but it does not give the amount of sugars or carbohydrates in one tablet. If you are following a low-sugar diet, avoiding added sweeteners, or monitoring your carbohydrate intake, the taste alone is not enough information. Check the nutrition declaration or supplement facts panel on the package for the carbohydrate and sugar values per tablet. A natural flavouring can be present in a very small quantity, so cherry taste does not automatically mean high sugar content, but the label is the only reliable way to know.
For people without such dietary restrictions, the flavour is simply a taste factor: it does not change how glycine acts, how long the tablet takes to dissolve, or whether it should be swallowed. Use the same sublingual method regardless of flavour. If you know you are sensitive to flavours or other additives, read the full ingredient list before the first use, and if you have any doubt, consult a qualified specialist.