Is a 0.2 ct heart diamond big enough for an engagement ring?

It reads as a delicate, understated ring. At 3.5 mm the heart is clearly visible but subtle; shoppers wanting a prominent center stone usually go larger.

How durable is the 1.3 mm band?

It is a slim band, so it bends more easily than a 2 mm or wider shank. It suits occasional or careful wear better than heavy daily use.

What does F–G color and VS clarity mean here?

F–G is near-colorless and VS means very slightly included, so inclusions are not visible to the eye. That is a strong grade for a stone this size.

Can I order it in another metal or gemstone?

Capucinne says the design can be made with gemstones of your choosing; contact them before ordering for a custom ring.

How do I pick the ring size?

Sizing follows the US ring size chart, and the size is chosen when ordering. Have your finger measured before you order, since a thin band fits slightly differently from a wide one.