"She looks without trying to understand."
Translation:Elle regarde sans chercher à comprendre.
When "chercher" is followed by a verb, it means "to try" or "to attempt" and must be followed by the preposition "à ".
To my knowledge, "chercher de " is not used anymore though you may come across it in literature from the past as it was employed by writers such as Proust:
Ex : « Dans ma crainte que le plaisir trouvé dans cette promenade solitaire n'affaiblît en moi le souvenir de ma grand'mère, je cherchais de le raviver en pensant à telle grande souffrance morale qu'elle avait eue; ... Proust, Sodome et Gomorrhe, 1922, p. 782 »
"essayer de faire [qqch] " = to try to do something.
"chercher à " and "essayer de " have equivalent meanings.
https://www.wordreference.com/fren/essayer https://forum.wordreference.com/threads/chercher-%C3%A0-essayer-de.1294692/ [note that the thread is written in French].
"Elle regarde sans essayer de comprendre." marked as correct
French prepositions are undoubtedly difficult for native English speakers--such as myself--learning FASL.
One thing I find helpful to remember is the "euphony" inherent in speaking French. If only modern-day English placed such an emphasis on euphony! It takes much practice, but the sound of the French language reveals its structure instinctively and hopefully, un jour, harmoniously.