What is the best scars cream that helps scars disappear?

Scars can'tdisappear. Sorry, but no cream will make a scar disappear. Scars can be improved with scar massage and, often, a cream will be recommended to facilitate that massage. Cocoa butter has worked very well for my patients as has the more expensive mederma. Sun protection and scar massage are much more important in improving a scar than the nature of the cream you use.
Scarring permanent. The body heals wounds and cuts through application of scar tissues. They often can improve with use of silicone based topical products from gel sheeting to topical gel application. It is thought to maintain a "moist' environment which is soothing and helps shorted the period of redness. Some surgeons accept use of mild digital massage with lubricant creams/lotions containing 1% steroids.