There is no guarantee that I could strengthen the organization well though.
I am a lifetime member of WaniKani, but I don't really think I can use it for a lifetime, as there is no guarantee that Tofugu will still be around in five years.
The grizzly bears will probably approach you, but don’t worry. It’s very, very safe. We guarantee it.
Evidence that something will be preserved is a form of guarantee, at least as long as the evidence is strong enough. Also, 保 also means guarantee, so use that to help you to remember this word.
This is a jukugo word, which usually means on'yomi readings from the kanji. If you know the readings of your kanji you'll know how to read this as well.