Let $E_n$ be a metric space, $B_n$ be a Borel subset of $E_n$ and $f_n:E_n\to\mathbb R$ be bounded and continuous for $n\in\mathbb N$ with $$\sup_{x\in B_n}\left|f_n(x)\right|\xrightarrow{n\to\infty}0.\tag1$$ Now assume $T_n$ is a bounded linear operator on the space $C_b(E_n)$ of bounded and continuous function from $E$ to $\mathbb R$ equipped with the supremum norm and assume the operator norm of $T_n$ is at most $1$ for $n\in\mathbb N$.
Are we able to show that $$\sup_{x\in B_n}\left|(T_nf_n)(x)\right|\xrightarrow{n\to\infty}0?\tag2$$
The problematic thing is that the contractivity only yields $$\sup_{x\in B_n}\left|(T_nf_n)(x)\right|\le\sup_{x\in E_n}\left|(T_nf_n)(x)\right|\le\sup_{x\in E_n}\left|f_n(x)\right|.\tag3$$
No.
Let $E=\Bbb R$, $B=[-\frac12,\frac12]$, $f_n(x)=\min\{1,x^{2n}\}$, $T_nf(x)=\frac12f(2x)$. Then $\sup_{x\in B}|f_n(x)|=2^{-n}\to 0$, $\|T_n\|=\frac12$, $\sup_{x\in B}|T_nf_n(x)|=1$.