7.5 stars.
I feel like there were some enjoyable moments. Take this from a guy who has seen hundreds of Hallmark films, this one doesn't stand out, but it's still above average. At this point you'd think I would lack objectivity, what with seeing dozens of "royal" romances, featuring a commoner and a prince etc. And yet, I like this movie just the same. If it was three years ago and this was my first Hallmark movie, I'd probably rate it somewhere around 8.0 stars, not realizing how repetitive this trope has become, nevertheless, it's still a good movie. There is a clear chemistry between the leads. Either that or a total lack of chemistry, and I misinterpreted it.
The story has been done, but the only difference is the setting is on a cruise ship on the Danube. There is a recurring role of an older woman who takes this cruise year-round and was in the first installment of "Love on the Danube..." and it's obvious she is there for continuity of the series. I wonder if they plan on doing a third one. If so, that would be fine. I don't imagine they will crank out six of them like the wedding veil series, because it's not quite as grand.
Hallmark can do more wedding veil episodes if they wish. I think people would welcome it back. On the other hand, these Danube episodes are a bit lackluster in comparison, because there is no mystery or legend involved, just generic romance. But, for the last time, I must point out that this is a good love story. I highly recommend it. The acting, romance, and cinematography are on-par.