Let's consider a symmetric matrix A.
If for each row, the diagonal entry is equal or larger than the magnitude of any other element, that is
$$a_{ii} \geq |a_{ij}| \quad\text{for all rows } i \text{ and entries } j , \,$$
then the matrix is positive semi-definite
It's false, I've just this counterexample.
$$\begin{pmatrix} 1 & 0.9 & 0.9 \\ 0.9 & 1 & 0.1 \\ 0.9 & 0.1 & 1 \end{pmatrix}$$ is indefinite, since the eigenvalues are $0.9$ and $(21 \pm \sqrt{649})/20$.
From this answer: Is this a positive semi- definite matrix