"I think I played smart tennis today", said Halep, who's looking to repeat her 2016 win here.
Romanian Halep will now meet the victor of the late semi-final between defending champion Elina Svitolina of Ukraine and U.S. Open victor Sloane Stephens for the title on Sunday.
Bertens, who committed 31 unforced errors in the match, saw her run through the tournament end after upsetting No. 8 seed Petra Kvitova of the Czech Republic and ninth-seeded Czech Karolina Pliskova earlier in the week.
"I was very sore when I woke up", she said.
Halep broke the third-seeded Stephens with a crosscourt victor to take a 5-4 lead and serve for the set. She beat François Abanda and Carla Suarez Navarro, improving her mark against qualifiers in 2018 to 6-1, with sole loss coming in first match of the year against Giorgi at Sydney. A crosscourt backhand saved one and Stephens netted a return on the second.
Svitolina will meet reigning US Open champion Sloane Stephens in the semi-finals, after the American thrashed Anastasija Sevastova.
The second set went much quicker with Halep winning seven of the last eight games. I mean, when you're playing good matches in big tournaments like this, I don't think it's peaking too soon.
The American returned the compliment.
Stephens had no such success in doubles, where she and Eugenie Bouchard of Montreal fell 6-4, 6-2 to Latisha Chan and Ekaterina Makarova in a quarterfinal. I was just trying to stay longer in that set.
For more sports coverage, visit the ABS-CBN Sports website. Halap broke twice more to open the second set.
"We played a good match", Stephens said of their showdown at Roland Garros. It proved a real battle, but one from which Halep eventually emerged a 7-6 4-6 7-5 victor.
"I feel like my return is growing up, I have more confidence", added Halep.
"Hopefully I'll play very well for two sets".
In the semifinals, Barty will face the top seed and world No. 1 Simona Halep, the 2016 Rogers Cup victor who defeated sixth-seeded Caroline Garcia 7-5, 6-1 in one hour 28 minutes.
"I hit some dropshots, which I don't normally do, because I was too exhausted", said Halep, who has reached at least the semifinals in four straight Rogers Cups.