"Biletul meu este dus-întors."

Translation: My ticket is round trip.

[Coriander18]

Should this be a return ticket rather than round trip? Does the ticket take one in a loop back to one's destination in one go? If so it is round trip.

[Howard]

"Round-trip ticket" means that the same as "return ticket" even if you find the latter more logical. Both terms should be accepted.
The Romanian is similar to the French: "aller-retour."

[WarsawWill]

"return" = BrE
"round trip" = AmE

https://learnersdictionary.com/definition/round%20trip

[Susan62877]

It's a return ticket. It's the same in Italian: "andata e ritorno"

[WarsawWill]

"My ticket is a return" (British English) accepted. Like most DL courses, this one uses American English, hence "round trip".