Guild Wars 2

Hello.

I was just wondering if the Gem Store item, Digital Deluxe Upgrade, comes with the HEART of THORNS expansion. I am currently on my base game.

No, the Digital Deluxe Upgrade does not include HoT. https://wiki.guildwars2.com/wiki/Digital_Deluxe_Upgrade

To add to RoseofGilead’s answer, you can’t buy Heart of Thorns for gems. Along with base game’s “Deluxe” upgrade, there’s another for HoT (Guild Wars 2: Heart of Thorns—Digital Deluxe Upgrade) but it only gives you some bonus goodies, not the expansion itself.