I am hiring junior product marketers. Hiring someone with experience is easier often as they have something relevant to talk about. I am hiring a junior / near fresher. So, no product marketing experience is expected. What things do I look out for? What questions do I ask? Any assignment that you can suggest?

When hiring a junior product marketer, I try and balance between hard and soft skills. For hard skills, I check to see if they are good at 

1. Diagnosing the market
2. Identifying pains and benefits
3. Writing. 

I can't emphasize that last point enough. Make sure your junior PMM is a great writer because they will tend to be your content engine. 

For soft skills, I check to see if they're good at influencing direction and are genuinely a good person to be around. 

Questions that I would ask to test the aforementioned would be:

• Tell me about a product that's good, but not marketed well.
• How would you describe to someone who was not familiar with our company or products?
• Tell me about a time you've influenced people without any authority?
• What is your favorite product? (It could be anything)
• Who is the target?
• What are the key benefits?
• Who are the competitors?
• How should it be packaged, if differently than it is now?
• Tell me about a time you encountered a road block and had to change direction?
• What do you like to do outside of work?
• What are two professional development areas where you would like to or that you are working to improve?

This is a fun challenge! Because most junior candidates are extremely eager to learn and super coachable. I'd ask:

• Does the candidate have excitement around the product? Or do they believe in the vision? Ask them how they connect to the product or company? For example: when I hired junior PMMs for my SMB business, I'd ask them for their favorite small business. 
• Ask them to do a trial of your product and see what feedback they provide. This one is a good one because that's the product they will be working on and it helps to see how they think about product strategy. 
• Ask them to come up with a tagline for the new product/feature. This would help you see what factors they take into consideration and how creative they can be. 
• If you are in the B2C business, ask them for their favorite product and why. Gives you a glimpse into how they analyze a product and what catches their attention. 

In the B2B world, I wouldn't consider hiring a product marketer who is truly new to the workforce. They will need too much handholding and don't have experience with a variety of tasks---I want at least 2 years of experience in a relevant role such as sales, demand generation marketing, consulting, product management, etc.

That said, I suggest looking for clear writing and communication ability as a minimum qualification.

The best product marketer who ever worked for me was a junior guy with no previous PMM experience. He really impressed me with his digital knowledge and customer focus. And he was eager to learn! I hired him despite reservations from some others because I knew he could bring in a digital-first perspective that the rest of us just didn’t have. The last question I asked him was what he was hoping to achieve in his career and he told me that he wanted my job. That sealed the deal for me. His development curve was astounding and it’s great to see how his career has blossomed since then.

To me, it’s about what character and abilities you observe in your candidate. With a few years of experience, can he/she replace you? If the answer is yes, then you should strongly consider hiring them.