You need to use a tv wall-mount bracket, which can screw into two studs and adjust to match your tv mount points.

If you can’t get a bracket you could attach a length of strong wood to the wall screwed into two studs, and then mount the tv to that wood in at least two points.

I wouldn’t trust it with just one side in a stud.

This is the mount I usually use: https://www.costco.com/Kanto-40"---90"-Full-Motion-TV-Mount.product.657260.html. I’m in the USA, but a similar one might be available in your country. It’s somewhat expensive, but very heavy duty. Uses four or six bolts into the wall (across two studs), can hold up to 150 lbs (~68 kgs), and is fully adjustable - you can tilt the TV up and down, and swivel it almost 90 degrees left or right. I’ve got two of them - One with an 83 inch TV and the other with a 65 inch TV.

Will it hold? Probably. Is it a good idea? Probably not.

Good screws to attach one side of the mounting plate to a stud will definitely be enough to hold the weight of the tv and the mount. That said, if you ever adjust the tv, that will put a lot of pressure on the side that is only attached to the drywall. Even if you use drywall anchors, they’re not meant to support weight/force in that way. The drywall will get messed up, the mounting bracket could feasibly bend given that it’s mounted securely on one side and not the other.

That’s kind of the worst case scenario. I would go for the peace of mind and install blocking that spans the studs which you can attach the mount to very securely.

I have a few arm tv mounts that fasten vertically to one stud. You should look into one of those instead of having to fasten a whole board on the exterior of your drywall. Less work, less holes

monoprice.com is a good source for inexpensive high quality tv wall mount brackets. you’ll also end up wanting to hide the cords in the wall soon enough.