trust
Investors trust trust funds for long-term security.
The sentence describes investors relying on financial trust funds for long-term security.

Meanings (pronounced /trʌst/)
to have confidence or faith in; to rely on
- I trust her to make the right decision.
- Don't trust everything you read online.
a legal arrangement in which property or money is held by one party for the benefit of another
- The estate was held in a family trust.
- Investors poured money into the new investment trust.
Word origin
From Old Norse traust ('confidence, help'), from Proto-Germanic *traustam, from Proto-Indo-European *deru-/*drew- ('firm, solid'). The same root produces 'tree' (literally 'a firm thing'), 'true' (firm in adherence), and 'truce' (a firm agreement). The legal/financial noun sense ('a trust fund') developed in Medieval English from the metaphor of holding property 'in trust' for someone — i.e., faithfully on their behalf.
Fun fact
'Trust', 'true', and 'tree' all come from the same Proto-Indo-European root *deru- meaning 'firm, solid' — the metaphor being that a tree, an oath, and a faithful person all share the quality of being firm, unmoving, reliable. To trust someone is etymologically to hold them as solid as a tree.