Ooooh, you just stepped into my old stomping ground, my friend.
Actually, that kind of question comes up a lot in self-defense forums.... Usually comes up when someone is or knows someone who is involved in an incident that rattled their sense of safety....
But there's nothing wrong with that, as it is a perfectly normal human reaction.
However, a gun won't help you.
At least, not initially. You can't rely on any external devices to provide you safety.
However, you did say the magic word, "Training". That may be the most important factor; to become more informed, aware, prepared, and ultimately trained. The human factor.
Otherwise, simply having a gun will not make you any safer than simply having a car can make you any more mobile. Both require human skill and training before these tools can become of any effective use to you.
In fact, a lot of extremely well-trained self-defense gurus out there don't even carry guns. Or knives. They are so well-trained that they can typically improvise. Well, that and it may be due to legal limitations....
But I'm starting to get off on a tangent. Securing a home does not require weaponry. In fact, the most important tool you'll need is a cellphone, and possibly a flashlight. After that, it's just a series of planning and preparation for contingencies, follow good safety procedures and habits, and ultimately to ingrain safety into your psyche.
However, if you do decide that a firearm is something you wish to pursue, I would treat it like a car. Be sure to know your laws first. Be sure to get basic firearms training first, which emphasizes firearm safety. You can do all that before you even own a firearm. In fact, it's what I personally recommend as the ideal way for people to start out.
After that, like a car, then you are "certified" to handle a firearm on your own.
One last food for thought: Although I've owned several firearms in the past (and have even built my own AR rifle), I currently don't own nor am I relying on firearms to secure my home. And yes, I sleep pretty soundly at night.