Learn English – It is the best movie<,> I have watched before!

• Smelling something means you're doing the smelling, and the thing you're smelling is something.
• Smelling of something means that you smell, and what you smell like is something

She smelled of ...

She smelled like

... sun and daisies with a hint of river water.

With a small amount of river water

Collins:

hint (3)

a small amount; trace

There are two issues here.

1. As Cardinal says, need sometimes behaves like a modal verb: 1) taking a 'bare' infinitive instead of one marked with to, 2) uninflected for 3d person singular, and 3) deployed without do support Specifically, it may be used this way in negatives and questions.

   Need he pursue this any farther?
   He need not pursue this any farther.

   But this use is not obligatory. You may also employ it normally, with a marked infinitive and do support.

   Does he need to pursue this any further?
   He doesn't need to pursue this any further.

2. "No X need apply" is a joking adaptation of a phrase from the last era when the US was suffering from severe anti-immigrant sentiment: when jobs were posted in newspapers and on businesses they were sometimes accompanied by notices that

   No Irish need apply
   No Italians need apply

   meaning that Irish or Italians or other immigrant group should not bother applying for the job since this employer would not consider hiring them.

   The shampoo puns on the two meanings of apply to assert its superiority to "ordinary" brands.