These are three words with a very similar sound to them but with vastly different meanings.
Accent is what we encounter in the speech of a lot of people, and it can be very irritating at times. Its dictionary definition is:
1. A stress on a syllable to aid in the pronunciation of words; a stress, an emphasis: “The word ‘woman’ has its accent on the first syllable.”
2. Pronunciation, enunciation, or modulation of speech: “He speaks with a British accent.”
3. A hint, touch, detail: “The hall was painted white with just a slightly blue accent.”
Ascent represents a rise, a climb up the stairs (metaphorical or physical) if you wish to label it that ways.
For example: “The manager made a careful ascent up to the roof of the building.”, “The ascent to the top of the mountain was difficult.”
It is also used a symbol for advancement or progress: “He has made a amazing ascent form a sales boy to manager of the store within the last 3 years”
Last but not the least, assent means to comply or to agree to something; to consent: “The assent of the boss is required before starting out any new venture.”