the safest wallet is the offline wallet but there is still a risk that if the pc where you keep the offline wallet is destroyed then you can not do anything, print the wallet on a old printer with no internet connexion and no memory, then you can still lose the paper, so there is no safe, there is always a risk
It's pretty tough to get coins 100% secured because there is a lot of software that can break wallets. Just keep it encrypted and hope for the best.
I agree it will be impossible to have it 100% secured. You can't secure everything but we can make it harder so that it will take a long time for hackers to break in.
I hold my coins mostly online because i think this is better than storing it on your laptop. They can easily steal it with a wallet stealer.