Most likely you are getting false positives. Do the following:
1. Contact G support and request to send you the infected URLs. If you see .js/.css/.jpg/.png/.ico files then most likely it's a false positive. From there go to steps 2+
2. Make sure that you uninstall all nulled plugins/themes (if you are using them). In case you really need a nulled plugin, make sure to get it from a reputable source or buy it.
3. Install and use cloudflare for your site /i.e update the name servers to the provided name servers by cloudflare.
4. Install a caching plugin if you don't already have one. I'd suggest to go with W3 Total Cache or WP Rocket.
5. If you are using W3 Total cache, just download and important the settings from here
https://www.dropbox.com/s/7wywhbjemcn6fm0/w3 total cache settings march 2019.json?dl=0
6. This is the most important step: Configure your caching plugin with a CDN. I'd suggest to go with Cloudfront since it's the cheapest option, but you can use whatever you want. This will serve your 'infected' files from a CDN, so all the .js/.css/.jpg/.png/.ico files will no longer be infected.
7. Usually within 3 days if everything is configured properly, all ads will be automatically reactivated and you will no longer see a message for malware next to your ads. If this does not happen, contact G support as well with a request to send you a new report. From here:
1) Either there are no problems and they can manually activate your ads.
2) There might be some URLs left to take a look at and from there you have to take specific steps based on your particular case. I cannot help you further if you get stuck and i don't know what is the issue, so if you get stuck, feel free to PM me and i will take a look.
P.S: Additionally make sure that you don't have any 404 errors or redirection going on. Use GT metrix for further scanning.
Also, if you are using Google Tag Manager, make sure that you don't have any malware messages there as well.