Can I enter Croatia providing a bus ticket to Slovenia as proof of onward travel?

I am a brazilian going to travel to some places in Europe, but I don't have my entire itinerary planed yet. All I have right now is my flight ticket to Croatia, and a bus ticket to Slovenia (from Croatia). I also already rent an accomodation in Croatia.

I know I can stay in Croatia without a visa for 90 max, but I also know that the border may require a proof of return to Brazil or onward travel to let me in.

I would like to know if my bus ticket to Slovenia is enough proof for the border officer to let me in.

I am in Bangkok now, in case it is important.

Edit

I already checked a lot of resources on the internet, and from my understanding, the bus ticket is enough, because Croatia is outside of Schengen. I am only asking this because I just check in for the flight, and the girl from the air company said that maybe they will deny my entry there because I don't have the return ticket to Brazil (she let me check in and I am taking the flight normally though), but that goes against everything that I found on the internet, so maybe I missed something :(