Solution
= Solution
Given $\varepsilon>0$, the <Cauchy sequence> property gives $N$ with $d(x_m,x_n)<\varepsilon/2$ for all $m,n\geq N$. Fixing $m\geq N$ and letting $n\to\infty$ yields $0\leq d_m\leq\varepsilon/2<\varepsilon$. Therefore
$$
\boxed{d_m\longrightarrow0.}
$$