His wife responds to this with the exact same feelings. To her he is like an apple tree among the trees of the forest. You do not expect an apple tree in a forest. If there were an apple tree there, it would immediately stand out. This tree immediately draws her attention, and it gives fruit to her. That one tree that stands out for her is the one for her. She loves him. It is so good for her to be with him and to sit in his shade. Life with him is a fruitful life for her. That fruit represents his special love for her. It makes life sweet; it makes life good.
She also longs for him physically. With her tongue she also wants to touch him intimately. She does this only with him. She wants and is allowed to kiss him in a special way. Her tongue may also feel his intimate love.
3 As an apple tree among the trees of the forest, so is my beloved among the young men. With great delight I sat in his shadow, and his fruit was sweet to my taste.