Occasionally I have cause to do a deep dive into word meanings.
Hope as a concept means 'confident expectation' and relates to the idea of respectful acknowledgement of one's duties and obligations, especially as owed to someone greater than you, prostrating one's self to show this service.
True relates to the word tree in the sense that a tree is not easily moved, compared to a stone boundary marker for instance. Possibly also relates to health in the sense of wishing someone to be as healthy (strong) as a tree.