Is a lab-grown diamond a real diamond?

Yes. It has the same carbon crystal structure as a mined diamond, with the same hardness and sparkle. The difference is origin: it was grown in a lab rather than formed underground.

What do VVS1, D and excellent cut mean?

VVS1 is very, very slightly included, so flaws are hard to spot even under magnification. D is the highest colorless grade. Excellent cut is the top cut grade and drives how much light the stone returns.

Will a 2 carat diamond look too large?

On most hands a 2 carat round stone reads as a bold statement. It suits someone who wants the ring noticed; if you prefer subtle, a smaller stone in the same grade is the usual choice.

Does a lab-grown diamond hold its value?

Less than a mined diamond. Resale is weak because lab-grown supply keeps growing, so buy it for wear and appearance rather than as an investment.

What should I check before buying?

Ask for the grading report and confirm the metal and setting type, since those are not stated here. A high grade stone in a weak setting is the common letdown.