deepen

Compared meaning: to make a feeling or effect stronger (verb).

比较义项：使（感觉、情绪、程度等）更强烈、更强（动词）。

• intensify

  The general, neutral verb for becoming or making something stronger in degree or force; used for storms, pain, conflicts, competition, feelings — the default choice in both everyday and formal English.

  语气中性、最通用的词，表示程度或力度变强／使变强；可用于暴风雨、疼痛、冲突、竞争、情绪等，是日常和正式英语中的默认选择。

  The pain in his knee began to intensify after the long hike.

  长途徒步后，他膝盖的疼痛开始加剧。

• deepen 本词

  Suggests growing richer or more profound over time, not just stronger; typically used for relationships, emotions, understanding, mystery, or voice — implies gradual, lasting change rather than sudden force.

  强调随着时间推移变得更深厚、更深刻，而不只是力度变强；常用于人际关系、情感、理解、神秘感或嗓音，暗示渐进而持久的变化。

  Years of working together helped their friendship deepen into real trust.

  多年共事让他们的友谊逐渐加深，变成了真正的信任。

• heighten

  Means to raise the degree of a sensation, emotion, or effect, usually caused by something external; common with words like sense, awareness, tension, anxiety, especially in descriptions of atmosphere or drama.

  指提高某种感觉、情绪或效果的程度，通常由外部因素引起；常与“感觉”“意识”“紧张感”“焦虑感”等词搭配，多用于描写气氛或戏剧效果。

  The dim lighting and slow music heightened the audience's sense of dread.

  昏暗的灯光和缓慢的音乐加剧了观众的恐惧感。

All three mean to make something stronger. Intensify is the general, neutral word, for a storm or conflict. Deepen suggests growing richer over time, for relationships or understanding, not water literally getting deeper. Heighten raises a feeling from outside, not literally making something taller.

这三个词都表示“变得更强／使更强”，但deepen偏向情感、关系或理解等抽象事物随时间“加深”，heighten强调由外部因素“提高”某种感觉或效果的强度，intensify则是最中性、最通用的说法，各种场合都可以用。这里不比较deepen表示“（水等）变深”的字面意思，也不比较heighten表示“使变高、加高”的字面意思。