First, a spelling issue. Were you trying to spell Solingen? It's not a brand. It's a city in the Ruhr, famous for cutlery for hundreds of years. If a knife has only the city name, I'd be suspicious of the quality. Usually, they have a brand name , like Puma, Henckels, Kissing Crane, etc.
I've never heard of an "out the front knife." Might you be referring to an assisted opening knife? Kershaw has some good ones. Mine is a Model 1550ST. It's a good knife, but I'm reluctant to carry it in a pocket, lest the spring assist activate if the blade gets rubbed on something. When I carry it, it's in a Cordura belt pouch. Usually, it lives in a bookcase.
I'm not sure if I'd suggest it to a one-handed person.
Have you considered the Swiss and German military folders by Victorinox? These went into production about 2008, replacing the prior issued models. The main blade has an opening that can be used like a Spyderco blade, to pivot the blade open one-handed.
If by your term, you mean a blade that slides out of the handle point first, like the German paratrooper knife, they're generally illegal, banned as a gravity knife. Probably also a little large for your lady.
Is it legal to carry a small sheath knife where you live? The Buck Model 102 or 105 or the Puma Hunter's Pal, or the Fallkniven F-1 would be good choices. Fallkniven also has a Woman's knife that may be just what's needed. The Mora firm in Sweden offers many good, inexpensive knives, from maybe $20-25. Although both are Swedish, they are a far cry from the much more expensive Fallkniven line. Fallkniven holds a Royal Warrant of appointment to the King of Sweden for knives, and the F-1 model is the official Royal Swedish Air Force pilot's survival knife. The S-1 with five-inch blade is one of the finest all-round sheath knives ever designed. There are several sheath options.
Have you looked at Spyderco's lockblade folders? I have a Delica and a larger one, I think an Endura. I use both and they've been very satisfactory. My Spydercos have partially serrated blades, but other versions have normal edges.
A person with one hand is going to be pressed to operate any folding knife, especially one with a lock. I really think the answer is s small sheath knife, if legal.