"not only" is correct and usable in written English.
You can use it to add additional information to a sentence. For example: "The school not only guarantees an excellent education, but also provides social and extracurricular activities for students."
Accurate power capability prediction can not only guarantee the safety but also regulate driving behavior and optimize battery energy usage.
Such a kind of model reduction not only guarantee the FD performance, but also reduce the system dimensions.
The designed controllers not only guarantee the stability of the closed-loop systems, but also obtain the disturbance attenuation ability.
The resulting fuzzy controllers not only guarantee that the closed-loop fuzzy system is quadratically stable, but also provide a guaranteed cost on the H2 performance index.
A successful omnichannel strategy should not only guarantee a retailer's survival--no small matter in today's environment--but also deliver a revolution in customers' expectations and experiences.
"Ringfencing money would not only guarantee results, but also create a more stable space for BAME talent on screen and behind the camera".
Targeting tourists not only guarantees worldwide headlines for those responsible.
It not only guarantees the freedom of speech, it also recognises the freedom to receive information.
This not only guarantees a full-flavored stew but also reduces spattering and stove-top mess.
The use of PDMS as intermediate molds not only guaranteed the easy demolding, but also enabled the novel enclosed casting.
Brenner not only guaranteed each fighter $5 million, but also watched Frazier win one of the great battles, a 15-rounder.
