well balanced 
adjective
(Of a person) emotionally stable: I saw her as well balanced and fulfilled...
- For instance, Mariese is a very rational, well-balanced person and does not believe in fate.
- It's important too to find normal, sane and mentally well-balanced people to be around with.
- Today, it is assumed that motherhood is a stressor and that the demands of parenting are likely to tip formerly well-balanced women over the edge.
Synonyms
sensible, well adjusted, reasonable, rational, level-headed, sound, practical, discerning, logical, able to think clearly, lucid, clear-headed, coherent;
steady, stable, responsible, equable, self-controlled, even-tempered, sober, down-to-earth, matter-of-fact, with both one's feet on the ground, in one's right mind, in possession of all one's faculties, mentally sound, of sound mind, sane, normal, right in the head;
Latin compos mentis
informal all there