Actually distilled tastes better than other waters, just without the so called "mineral" garbage that is present in mineral waters. Store bought distilled water stored in plastic containers can taste bad, I tried that. Some of them are actually not distilled but deionized, that´s a different process and can be harmful for human consumption, but it can be more cost effective for producers. So if you buy it from the store, make sure it´s true distillation. True distilled water usually has 0 or only a couple of TDS (total dissolvable liquids). If you speak to long term distilled water consumers they all say that normal water tastes bad after doing the change. That makes sense, because it´s pure water without contaminants. Try distilling your water for a couple of cycles, then scrap off the white residue that is left in the tank and eat that. It´s so good you´ll want to vomit. Adding artificially processed liquid mineral drops to distilled water is like adding raw milk to pasteurized, to make it healthy again. Complete nonesense.
It can take some time to get used to distilled water, but I consume it since quite some time now, for cooking, pure drinking and making tea, to no ill effect. It can have a cleansing effect, that can sometimes be a bit too much, but that depends on the person. I do sometimes make breaks of drinking it, because I drink carbonated water which is very acidic and helps kill candida as it raises stomach acid. Distilled water, once it gets in touch with CO2 gets acidic on the PH, but not as much as I would need. I also drank naturally sparkling water, just as it comes out of the source, like AV suggested, however my stomach does not like all brands I tried.
I know of some people that had issues with it, so it fits for some people and for some it does not. It might be the cleansing/detox effects that it can initiate, you might take longer to get used to it, or you simply don´t tolerate it. There is some very good info about distilled water on the net, also on yt unless they took it down already. Lastly, rain water is naturally distilled water. Only problem is that our environment is contaminated, so drinking rain water might not be a good idea in some regions. The only downside I would see from distilled water is that apparently it has no energy, people call it "dead". To counteract that you can add some shungite on the outside of the distiller, or you let it go through a vortex to mimic the natural flow of waters in rivers and the like.
So to answer the question, you don´t make it safe, it is safe already because you filter out all the contaminants. But it can take some time to get used to it, or you sometimes need a break of it. If you drink mineral water you drink dissolved limestone that the water picked up and dissolved on the way out of the spring source. Just look up calcium carbonate, the type of calcium present in mineral water, it´s the same type you find in egg shells, just this can lead to health problems already. There is a lot more info out there..including the spiritual component..you just need to know where to look for. They drink it on the ISS, in submarines, it´s praised by real doctors...Anyhow, I´ll finish with the below:
DR. ALLEN E. BANIK:
“What we as scientists and the public have never realized is that minerals collected in the body from water are all inorganic minerals, which cannot be assimilated (digested) by the body. The only minerals that the body can utilize are the organic minerals (from fruits and vegetables). All other types of minerals are foreign substances to the body and must be disposed of or eliminated.”
“Distilled water then is water of the purest kind. It is odorless, colorless and tasteless. The divine purpose of water is to act as a solvent. In nature, water in evaporation is so fine that your eye cannot perceive it as it is drawn up into the clouds. Then it falls as rain, keeping the earth from being parched and burned. As a solvent, it dissolves rocks and soil. It figures in the transport of nutrients into plant life.
In the human body, water fills similar functions. …Distilled water acts as a solvent in the body. It dissolves food substances so they can be assimilated and taken into every cell. It dissolves inorganic mineral substances lodged in tissues of the body so that such substances can be eliminated in the process of purifying the body. Distilled water is the greatest solvent on earth —the only one that can be taken into the body without damage to the tissues.”