Graphic Designer here. I know my fonts. (Still not a lawyer though)
Many fonts, particularity commercial fonts you buy, don't necessarily grant you a license for embedding the font into files or software. Encrypted or otherwise.
You may need a special license for that. Embed the wrong font in your game without checking your license and you could land yourself in serious trouble.
You need to have an "Application License" Which is not the same thing as a commercial license.
However, that's if you're using the actual font files/data. If you convert the font into a sprite based font (No longer editable and re-sizable) then it should be fine for most fonts. It's kind of a weird technicality, but there's reasons for it.
If you're using a font that the user already has on their computer, then you can use it in your game. The font technically isn't part of your game at all, in that case. This can be a major problem if the user doesn't have the font, but if you keep to standard fonts that come with windows, like Times New Roman, for example, that problem shouldn't crop up.
The thing is, with RPG Maker in particular, using the font file in your game's fonts folder basically counts as re-distributing it. So you need a license that lets you redistribute the font, no paid font will allow that, and many free fonts still don't allow you to do that. (So the user would have to go download the font directly from the font creator's page separately) And if your game is commercial, you would need a license that would actually allow you to RESELL the font as part of a package, which no commercially protected font would allow.
Long story short, the solution is to use open source fonts. They usually have an "OFL" Open Font License, and you can basically do whatever you want with those fonts, including packaging a copy of it in commercial games and reselling it, so long as you keep the actual license document in the fonts folder with the font. Also, some fonts are public domain. Basically, check the license that came with the font. If it doesn't have a license, be safe and don't use it.
To clarify, you can "use" default system fonts because they are not a part of your game software. If you have a font that you cannot distribute the data for, using it in pre-rendered images such as in HUDs and interfaces, cutsceene graphics, as text elements in your game art, or even as a sprite based font are usually allowed. It's just the actual font file you need to be careful with.