What should be included in a guarantee letter from my Thai spouse for a Multiple Entry Non-O visa application based on marriage?

Hi, i've read quite a lot here, but still have one question about the Multiple entry non O based on marriage with a Thai national, which i want to apply for at HCMC.

Their website says that, beside other documents, a guarantee letter written in thai from Thai spouse is required.

What should my wife guarantee in that letter? Is it just a simple "my husband is applying for a non O visa and i guarantee that the given informations are correct" or what else should this letter contain?

We just married a few days ago, have a 4 months old son and i am german, currently staying here on my second ED visa.