"For every investment, return and security are in opposite directions, meaning the higher the return, the higher the risk."
Whether it is so depends on the choice of the system. Risks of bonds, stocks, real estate, currencies, commodities and precious metals are of a different nature.
In the civil law book BGB is defined that a loan, (§ 488-490 BGB) secured with a mortgage on a property in Germany occupy, represents a safe plant (§ 1806 and § 1807 BGB plant of ward money).
MG Grundbesitz GmbH offers investors land charges as collateral for a loan:
Security deposit within the meaning of § 1192 Abs.1a BGB.