The top-seeded Belgian prevailed 6-2, 6-2 against the Romanian fifth seed, who was playing just her second Tour event on grass, and is yet to drop a set.
She will face Andrea Petkovic in Saturday's final after the German seventh seed overcame Belgium's Kirsten Flipkens 6-7 (3/7), 7-6 (7/2), 6-4.
Former world number one Henin, champion here in 2001, is playing her first grasscourt tournament since cutting short her retirement earlier this year as she gears up for a shot at a first ever Wimbledon singles title.
In the men's semi-finals, seventh seed Janko Tipsarevic battled past defending champion Benjamin Becker.
The 25-year-old dropped a set before seeing off the eighth-seeded German 6-7 (5/7), 6-3, 6-4 to set up a meeting with Sergiy Stakhovsky of the Ukraine.
Earlier Stakhovsky, 24, hit five aces and converted all four break point opportunities to beat Xavier Malisse of Belgium 6-3, 6-4 after 67 minutes in their semi-final.
The 71st-ranked Ukrainian is bidding for his third title after Zagreb in 2008, when he beat Tipsarevic in the quarter-finals, and St. Petersburg in 2009.
Serb Tipsarevic, ranked 51st, is bidding for his first ATP senior title in his second final after Moscow last year.