The only free and comprehensive online etymological dictionary of the Spanish language
contentar (Verb) "to please"

15th cent. From Latin contentare 'id.,' from continere "to hold together" (see contener) and frequentive suffix -tare (see note under faltar).

Romance: Western Vulgar Latin: Portuguese conter, Galician conter, Catalan contenir, French contenir, Italian contenere; Eastern Vulgar Latin: Romanian conteni, conține