Consider, for $m\ge2$, the function $\varphi_m(x):=x(1-x)^m$ . So $$\varphi_m(0)=0\qquad \varphi_m(1)=0$$ $$ \varphi_m'(0)=1\qquad \varphi_m'(1)=0\ .$$ It is also easy to see that $\| \varphi_m'\|_2=O(m^{-{1/2}})$ (in fact, we may compute exactly both $\| \varphi_m\|_2^2$ and $\| \varphi_m'\|_2^2$ in terms of some rational functions of $m$, by means of a few Beta function integrals). For any $v\in H^2(0,1)$ define $$v_m(x):=v(x)+\big(v(0)-v'(0)\big)\varphi_m(x)-\big(v(1)-v'(1)\big)\varphi_m(1-x)$$ then clearly $v_m\in V$ and $\|v-v_m\|_{1,2}=O(m^{-{1/2}})$.